I totally get your frustration. Any leftist person, group or organization that ostracize people for being a little bit better materially than other people is completely wrong and shouldn't be taken seriously. The tech field is full of techbro ancaps, having a leftists there is already a step forward. We can't just confine ourselves to a few spaces and gatekeep who can and who cannot be a part of it.

It's like you said, you're orders of magnitude closer to the homeless than to the rich. You are not the enemy, and even if you were, you're still a leftist and any help is welcomed.

That all being said, I don't think it's right to say that this is the reason the left will always lose. First because the left is not an unified mass that thinks the same. There's a lot of different leftist ideologies and they all clash in some way of another, be it for a disagreement in how to organize or in how to achieve communism. And second, because this type of thing tends to be something you would see more on the imperial core where actual leftist thinking have been thwarted and made into a boogeyman, I don't know where you're from, but I honestly suggest you try looking for Marxist-Leninist groups and organizations.