Not sure how 'expert' the people are you refer to really are in terms of masks. It is tue that if you wear a cheap face mask or surgical mask, then they can become uncomfortable, particularly with exertion and can have a poor fit. If you wear a good quality one with a valve-- then that is simply not the case. I once worked for 3M Healthy & Safety Division for 5 years, who pioneered disposable respirators to compete with the old rubber ones.
You need an active carbon membrane version (N95 ++) to have any useful barrier to microbes on a short term basis but no face mask offers sustained protection. However, even the much ridiculed basic dust masks do have a use, in that they stop you touching your mouth and nose which studies show we do over 20 times per hour.