The point is not for those he criticises to listen to him. Corporate executives overworking and abusing employees, pushing lootboxes into children, and exploting BLM imagery to elicit fear aren't going to listen to voices telling them to perhaps not do that, no matter how friendly and kind the tone. The point is to make the general public aware of what these executives are doing, so that they may act accordingly.
And before you point out that the general public is mostly only concerned with their games and gives no shits about any part of the sausage making or political messaging, that's an oversimplification. The general public is not an unchangeable monolith, it's composed of individuals, and even individuals don't exist in a binary "cares / does not care" state; they can be brought to care more and more, eventually changing their purchasing habits over time. That is exactly what happened to me, and I would guess a lot of people in this forum. How the hell are people supposed to make informed, ethical purchasing decisions, even if they care, without people like Jim and Jason exposing these practices?
This "preaching to the choir" narrative assumes the existence of unchangeable sets of people (evil executives, alt-right douches, uncaring gamers, woke gamers, etc.) where no one individual is brought closer to a boundary by rethoric, let alone cross it. Which is demonstrably false, if only because GamerGate and the alt-right have been very effective in pushing people in the exact opposite direction for a while. Without people like Jim to push in the other direction, we're well and truly fucked.