What, you don't think American old-time alienates the general population? I mean the real stuff, not Old Crow Medicine Show.

Don't think we don't understand how protective you are about your trad music--we've got the same thing over here (I even know a few people who are quite protective of their English traditional music). There are plenty of American trad musicians who do NOT incorporate jazz in what they play and are meticulous about sticking to the European roots of the repertoires, although the roots may not always be English (might be Irish, might be Danish, might be German; there is regional variation). They are also meticulous about sticking with the stylistic conventions of what they play and how they play it. That doesn't mean that they can't do anything else, as you've noted, only that they know how to keep one separate from the rest. We don't all just lump all our musical influences together indiscriminately.