I reject the invitations too, but the fact is that they exist, there are (many) people who do them, the papers are published, they come up in searches, and the whole thing becomes a muddy mess.
Most people say “we’ll just don’t read/cite them” but the fact is that there is no clear red line; it’s all foggy. In order to look at a paper and say “I will not read you because you are crap” you need to spend some time with it, and if you have 2000 of them, that translates to a lot of wasted time. The reason why journals are supposed to do serious peer review was exactly so that we don’t have to do it ourselves.
Most people say “we’ll just don’t read/cite them” but the fact is that there is no clear red line; it’s all foggy. In order to look at a paper and say “I will not read you because you are crap” you need to spend some time with it, and if you have 2000 of them, that translates to a lot of wasted time. The reason why journals are supposed to do serious peer review was exactly so that we don’t have to do it ourselves.