I have trouble with this concept too. Had a meeting the other day with my banker, and he spent about 10 minutes complaining about comcast (their poor service) and then smiled and said "well at least the stock's doing well..." and I could only think of the Ouroboros. I questioned him about it - "why would you invest in a company you hate?" and he didn't have a good answer and agreed it was funny how things worked out. "On one hand I hate that their customer service is overseas, on the other, I'm glad their stock price is going up." It's cannibalism.
If we all participated in society this way (only invested in things we vetted completely and companies that were upstanding) would it not have an impact? I think this is inline with the idea that we need to take full responsibility for everything while we're here.
It's similar in nature to purchasing product is it not? The big difference being that the purchase directly supports operations, while the vast majority of equities are now merely bets on the future market value/future sums someone is willing to pay for those shares (so not as directly responsible for the operations of the underlying company). Even IPOs are simply reselling of major institutional money - so you're primarily supporting the banks putting together the IPO and not the companies themselves (as their shares have already been purchased).
Also I know you're vehemently opposed to crypto, but this argument applies to that as well - meaning it does have it's limitations when it comes to where you place your money.
I've slowly started to come to the side of the "better in my pocket" than theirs - as I've learned there is a lot more you can do with money than just "buy stuff."