I wouldn't assume that professional profilers make their profiles louder for a purpose though.
I don't want to assume that either, but I have to ask, then why do they do it? I'm not trying to make accusations, but when I make a profile, if I want to adjust the volume I simply adjust the profile volume, I don't go out of my way to adjust the EQ, cab and/or some post amp effect, it doesn't make sense unless there is a reason for it. Maybe some people think adjusting the cab volume has a different effect on the tone as opposed to adjusting the profile volume, I honestly don't know, but I think it's a valid question. Maybe they are right, I haven't tested this theory, I was hoping someone who knew for a fact would clarify whether one volume adjustment has an effect on the overall tone as opposed to the other would chime in.
To be honest, the thing that brought this to my attention was the fact that with commercial profiles I almost always clip the output unless I go through and turn down the various volume settings, and that just didn't make sense to me why I need to do that.