Shame on a single developer to want to be compensated for the work he's put into an app. How dare he try to make a living! How dare he go against your will! If you don't like it then move on. Publicly shaming a non-issue, lol.
Also, if you're so upset with an app "infested with ads" but you are savvy enough to be in the know about third party fediverse apps, maybe you should look into a whole home ad blocker.
Ostracizing someone for trying to make a living. What the hell is wrong with you?
For what it is worth, I won't be paying $100 for Sync Ultra either. But I'm not going around accusing a dev of hiring paid actors to promote his app that already has multiple posts on the front page of the fediverse.
You are not just "being critical" you're accusing them of being malicious and I am calling you out on that specifically.