It is a weird realization to understand that some people don't understand empathy for their fellow man. In many cases not simply don't have empathy, but don't understand it, like it is actually a foreign concept for them.
We see this when examining many dictators like Putin, that his entire view of international politics is shaped by this mindset that civilians are disposable pawns to be thrown away at the pleasure of those above them, and keeps making faulty assumptions of how other people will act based on this. The important takeaway I think is that when people immerse themselves deep enough in such cruel thinking, the cruelty eventually becomes second nature.
While other browsers technically exist, it is foolish to think that web browsers are a thriving diverse ecosystem right now, when 74% of all web-browsing is done using a Chrome-based browser. With their influence, if Google decided to start forcing changes on how websites function on a technical level, they could absolutely do that with little to stop it;- what are websites going to do, alienate a supermajority of their users?- And that is why people are so worried about things like Threads, because once a single company has supermajority control of a market, they can use that control as a weapon to get what they want.
I say this as an avid Firefox user: Firefox is niche. And the only reason Safari has 20% is because it is integrated with apple products, if it weren't for that, Chrome and Chrome-reskins would effectively be the only option.