This topic should be move on reputation since it’s all about forum member behavior towards the gambling discussion and this is not a gambling discussion thread.
His point of view against gambling while promoting one on his signature is responsibility of his campaign manager for accepting him to promote the brand. Heated argument is normal on discussion. Just ignore him if you don't like his post.
For some reason, I believe this thread should belong in the gambling board since the main question in the OP is why do you think the Gambling board is unethical. You can consider the title as clickbait and I used it because almost nobody has the same point of view as him. I already explained why it should depend on a person's point of view.
The campaign manager has nothing to do with it. The campaign manager will look for the posts he writes and he will get paid only if he writes five posts in gambling boards. If he does not, he is unlikely to get paid.