Google's acquisitions of Nest and Dropcam are the two which impacted me personally. Data ended up in the hands of people I didn't want, features were removed that I found essential. Perhaps others can volunteer their stories, I've largely opted out of IoT because of these experiences and concerns.

Suppose you buy a car from manufacturer A. You lose both keys (perhaps you and your partner each bring one on a canoe trip and capsize) so you have no choice but to ask the dealer to assign new ones. You find that Google now owns the entire brand A including its dealer network, and they only offer rekeying service in conjunction with an update that installs what you consider spyware. Do you opt out of the motor vehicle industry?

I opted out of the entire motor vehicle industry for far less.

There are malicious actors in the business of buying popular App Store apps and introducing malware into updates.

Or buying chrome extensions. Even domains.

There are reports about Saudi stakeholders co-owning few billion stake Twitter with Elon just to be able to install people who exfiltrate data used for tracking and arresting journalists and activists, for example.