It depends on your goals. If the goal is speaking and understanding it being spoken, it's one of the most orderly and consistent languages there is, with (non-typically for languages) clear and simple rules, grammar and modifiers.
Reading is similar until Kanji comes along and messes things up, but by that stage you could probably get by pretty well, both in the country, and by ingesting materials with simplified Hiragana alongside Kanji (which are common).
I mean, sure, if you exclude the most complicated writing system currently in use in any natural language, Japanese is simple. I hear Chinese is really easy too if you just do everything in pinyin.
Right, sarcasm off. Yes, the grammar is pretty simple. It has a mere three irregular verbs. The inflection can be somewhat unwieldy (温かくなかったら atatakakunakattara, if it were not warm) but it is nowhere near as complex as European languages.
But. You can’t just dismiss kanji. They are the essence of the language and, counterintutively, are what make it easy to read in long form. A stream of hiragana is almost illegible; you need the kanji to be able to pick nouns and verbs out. And outside of very limited contexts, furigana (phonetic transcriptions of kanji) are rare, so you need to a reasonable command of kanji to get by.
The context here is learning Japanese, ie a beginner. A typical way to do that with any language is to use the enormous wealth of resources aimed at either kids or learners. Including in this case many popular manga.
It's a context within which, of course, Furigana is widely available, as it's one of the ways Japanese themselves learn Kanji. And I would guess probably why it even exists, though I'm sure you could correct me on that.
Your view of Japanese seems to be from a very high level, encompassing its totality or close to it. At that level your assertions may be correct and relevant, but that's not where my comments, nor the OP with their post, are aiming.
OK, but you’re moving the goalposts. A written form of the language curated specifically for the purpose of learning is not really relevant to a discussion of the language, just as would be the case for any other language. That is not the language used in daily life. There are no furigana in a newspaper or on the Internet (technological assistance notwithstanding). Magazines, business communication…anything useful is off limits if you can’t read, say, 500 kanji at an absolute minimum. Anything more advanced, academia, etc. requires far more.
You think the goalposts have been "moved" because you've misinterpreted the context of this discussion.
The original post we are all commenting on is an introduction to some basic concepts of Japanese, aimed at programmers.
After learning several languages to a basic conversational level, Japanese was by far the most logical, simple, and had the least "gotcha's" or exceptions. On the whole it was a breath of fresh air compared to others.
My comments regarding the relative ease Japanese can be learned to a basic, useful level versus same attempted in other languages stand. Attempts to reframe them as regarding a level of complete mastery won't alter that.
Can you explain why a stream of hiragana would be unreadable? It's a phonetic alphabet, right? Shouldn't it be just as readable as the phonetic alphabet for any other language?
It's difficult to skim the stream of symbols and instantly recognize concepts. Think of a word finding box puzzle in English (https://duckduckgo.com/?q=word+finding+puzzle&iax=images&ia=...). It helps if you add spaces and periods, but I still think kanji make it easier to quickly pick out concepts.
In this video, Yuta compares different ways of writing the same sentence and discusses efforts to eliminate Kanji: "Why Do Japanese Still Use Kanji?" • https://youtu.be/O27TgLW6pCU?t=220
Another analogy: I find the flat enunciation of "voice to text" on my phone a bit difficult to follow. I can understand if I pay attention, but I can't passively listen and multitask like I can with human read text (@see - The Guardian's "The Long Read" podcast).
I can read only a limited number of kanji (or rather, words written with kanji), but even that makes reading much easier. Books for small children are written in Hiragana, with spaces, and in theory that should be as easy to read as English.. after all, it's easy to learn Hiragana, anyone can do that in a short time, and with practice you can learn to read it fast. But it's still tricky to read all-Hiragana sentences, even with spaces. Not sure I can explain why, more than the usual (and true) argument about the particularly large number of homonyms in Japanese. It's more than that. It's just much faster and easier to read 私 than わたし
It's interesting to consider that Japanese's relatively low number of discrete phonemes might result in a relatively high number of homophones, but if a preponderance of homophones is the problem, wouldn't listening to spoken Japanese be just as hard as reading hiragana?
On the contrary, listening to Japanese feels easier than listening to a lot of other languages, even for speech which you don't actually understand. The sounds are simple, there are a lot of vowel sounds. Straight forward vowels, not diphthongs, and in that respect it's a lot like listening to (slow) Italian.
There are a few run-on consonants in speech, but not many. Of course one runs into homophones in speech too, but there you also sometimes (but not always) have pitch to help you (persimmon and oyster are both written かき(kaki) in Hiragana, but the pitch is different, same for chopsticks/bridge), and there's context - if you understand enough of the language.
As an example, my wife owns a Japanese CD which includes a couple of songs originally from my own country, but translated to Japanese. Listening to that is very easy, I hear every word.. it's much much harder to actually get the words if I listen to the original in my own language! And these are simple songs.
EditAdd: What I said above is correct in the sense that it's easy to listen to Japanese, as in actually hearing the words, but yes there are homophones which sometimes make me, a low-intermediate speaker, not understand what I hear. I hear "another" similar-sounding word, unless there's pitch to clearly identify it, and then what I hear doesn't make sense unless it's a recording and I can re-listen.
Reading is similar until Kanji comes along and messes things up, but by that stage you could probably get by pretty well, both in the country, and by ingesting materials with simplified Hiragana alongside Kanji (which are common).