Nobody knows. See https://en.wikipedia.org/wiki/Hard_problem_of_consciousness

“niceness” from incels is very different from genuine niceness with no ulterior motive

I disagree.

its very easy to detect when someone is being Actually nice, and someone is faking a niceness.

That seems very naive to me.

one short two word sentence does not fit the rest of what he is saying

I disagree. The two word sentence fits precisely everything else he said, which seems to describe exactly the same behaviour with exactly the same end goal. There doesn’t seem to be any difference between “before” and “after”.

versus being nice as a means toward being his better self

No, OP said “which worked”, which implies that his being nice was not just a means toward being his better self but also a means to get what he wanted from other people. Like before.

Everyone knows you’re not being nice, you’re trying to manipulate them.

I was trying to be nice so they would want to be with me, not because I wanted to be nice.

After that I worked on myself.

worked on being more pleasant to be around.

Just be nice to people and don’t expect anything

show interest in other people’s hobbies - genuinely.

Which worked. By being less self absorbed and focused on getting a girlfriend, I became someone who was attractive

I see, so rather than trying to make people want to be with you by being nice, you should be nice to people and then they’ll be attracted to you. Uhh… wut? Sounds like you haven’t changed at all.

trying to manipulate

Which worked

How is what you did “after” different from what you did “before”?

How can we make sure Zionists are held accountable when their genocide is over?

You can’t.