I suspect there is another reason. The bedroom guitarist has access to amps from well under £100 (I have for example a Vox DA20) that will emulate much bigger and costlier amps so long as you don't need balls to the walls volume or the real metal octivider grunt. But they have not got access to devices that will make their voices sound like their preferred singists. The budget pitch correctors start at about £300 and can sound nasty, and actually getting timbre corrected is a bugger without large cost and engineering skill.

It is largely ONLY folk music that takes the position "So - you don't have a voice that sounds like X or Y - figure out what you can do with the voice you have". It is also largely only folk that takes the position "So, you can't sing it in that key - try a different one".

These bedroom guitarists are largely conditioned through rock or pop music - and that is not about participation, but of top-down making markets for the masses. Where would Tin pan Alley be if people made their own music?

The fightback starts with each such participant - so get them to try to sing and applaud thier efforts.