When someones makes a claim about the general quality of the game game, sure. I dont care. When the claim is “SG hears others”, “sg does not like what veterans feel or wants”, or anything implying they robbed their Backers then I care, because the claim is based on pointless assuptions of what is in the mind of the devs and pollutes the discussion.
Also when the claims are specific inacurate claims about a promise that has been broken, then I also care. And yes, a subjective opinion is an invalid reason to support a factual claim. So I it is more than fair to point that an argument is invalid. That is how reason works.
In the same way, I can say an argument based on popularity is a fallacy and is an ivalid way to argue.
I can and I will also say when you attack me instead of attacking my arguments that you are making an ad-hominem attack which is another fallacy, and another invalid way to argue.