Okay, we've identified the problem is capitalism. Now what? Are you not at fault when you buy cheap crap from China you don't need or take your car somewhere you could have walked, because the problem is capitalism?
When crops are failing due to drought and kids are starving to death is pointing the finger at capitalism going to save them?
My point is, why do you think those oil and gas companies or big tech exist? Because there is a market for it because of consumer behaviour.
A profitable oil company is never going to just close itself down for the sake of morals. And even if they did, a different oil company is just going to take over their market share.
The only way we stop oil companies is by making them unprofitable, either through voting for legislators that will tax them or sanction them, or by taking away their demand.
And while your individual demand is tiny, the same as you single individual vote in an election. It won't have an affect by itself, but if lots of people band together we can make change.
And the first step of that is acknowledging it.