"Perl6" is how you write "Perl 6" if you have searched with a computer much. Most humans don't have a problem with seeing some big difference between the meaning of "Perl6" and "Perl 6"; computers aren't always as intuitive.
Most humans on this site seem to have no trouble understanding that someone who writes PERL means Perl, though said person will hear about it at least once.
Not from me. I guess not being alone in being a pain in the arse may be of some confort to you, but it isn't really of any comfort to me. ;)
I said "most humans" because most humans are not pedants (praise be to Allah). I suspect that "most humans on this site" are also not pedants (but that certainly isn't as clear as the prior claim) but it seems it is hard to throw a brick (aka "comment") on this site without hitting a pedant (aka "without getting 'hit' by a pedant").
Note that you claimed to not know what "Perl6" was, so I apologize for offering to enlighten you. Sarcasm is a bitch.
For my part, I'll continue to write "Perl6" for the very practical reason I gave. If some actually voice objections (because "Perl6" can be taken as a new name rather than the same name with a different version number), then I'll also continue to chuckle at them.