Spewing BS doesn't in this context seem to imply either lying or shilling for somebody else. It's a devaluing the opinion of no taxing the rich, and being disappointed at the expression of that opinion.
Parent said Petersen was "spewing BS... to protect his money", I suppose that may not quite be shilling, it's more being deceptive and greedy/crass? I am happy to accept clearer wording if you've got any ideas.
It’s having an opinion. An opinion that you just disagree with. We don’t need accusations of astroturfing based on a single comment.
To be clear, I never accused anyone of astroturfing, am just clarifying the top-level comment's remark.