Yes, and doing that in public is unprofessional. Its possible your buddy CH would be perfectly fine with a player still owned by the club would publicly question his decisions on social media, but most clubs & managers would not be fine with that.
Loads of players question Managers Decisions publicly. Kayal did it a few times on Social Media. Locadia would run to the Dutch Press. Hemed would run to the Israeli Press. - It ain't a big deal. You are getting enraged on behalf of Graham Potter for no reason. These things happen. Some players take it to heart. Others just accept a Manager's decision.
Your other point I refer to in a separate post because the terminology used was " Colonial "