Why would that mean they are suddenly untrustworthy? Anything they are doing online is using up time and energy that they could be using to produce income elsewhere. It is taking time and energy away from job and family. Why shouldn't they make some money at the same time they are giving away information for free? If they were demanding subscription fees before sharing anything, that'd be different.

I keep seeing comments about this that don't seem logical to me. If you don't want to donate or buy a t-shirt, don't. But that has nothing to do with their credibility.