It's not just about being abrasive. It's about posting negative comments when you have nothing to offer. If your reaction to something new is that you have absolutely no interest or wouldn't pay a few cappuccinos per month for it then guess what: no one cares. You're just polluting the thread with noise.

Helpful: this is interesting, but I tried it and it's missing these features that I would need to consider paying for it.

Not helpful: subscriptions are the devil!