The problem with that narrative are the Republicans. They think he represents them. And Trump is leading among them.
Why would I ignore republicans on who represents republicans?
It matters because Trump isn't an R, he's actually got a /lot/ of D leanings if you look at his stances. It matters because Trump picks up I's like me. You know I'm obviously not an R yea? So he doesn't /just/ represent R's like you're implying, but also a lot of us I's, and V's, and L's - that's I believe, a lot of why he's got so much Teflon, not because racists support him, but because he's cross-talking the party line.
A new "trend" where we label candidates entirely based on negative folks who happen to support them isn't the best idea for D's to run with either. OWS, BLM, and "undocumented workers" haven't resonated well with the majority at all - shit my mom's been a dyed in the wool D (one of those that just votes D no matter what) since I was born and she's voting R this year - specifically because of OWS and Sanders. The D's "vote base" right now is the like 20-30's who want full on socialism (but if they don't get Sander's a shit ton of the ones I know are, for some reason leaning Cruz - I'm baffled by it so don't ask me,) "most" of the AA's, illegal immigrants / Hispanic's, and LGBT's. The R's "vote base" has traditionally just been "Christians" but Trump is changing that, he's pulling in the parties who haven't had a real voice for ages and ages (I's, L's, V's) If the GOP is smart they'll follow that lead swing more moderate and keep us I's, V's, and L's next time around. Even if the R's lose this year, I think the wake up bell has been rung in the GOP that Christian's alone might not be enough anymore so they need to swing a bit. If the R's would just give up the religious based crap, they would gain a LOT of peeps; nearly every business owner in the country is an R frankly, but we've always been forced by religious bias to vote against R's. Plus, if the D's actually put Sander's in the WH, holy crap will that change the political field...
No matter what happens with the election honestly, I haven't been this hopeful for a change in the failing two party divide system since I "grew out of" that optimistic "we can make a difference" stage between being a kid and being grown up with a family (for me it was like 18-22 or so, but for most it's like 20-30ish.) I just hope the rest of the country is feeling what I've felt for so many years and deciding we've had enough of the kind of unthinking, automatic R's hate D's bullshit (ya know, my sig and all) As much as I've bitched about all my younger friends wanting Sander's this year, at the same time they're also distrusting the media bias and starting to research deeper than just sound bites on their representation - which is something I've not typically seen with them, nor in the general public. It's really great to see and its given me idk a new hope for America's future.

It's like we've finally hit that point where the ruling parties are at such polar opposites that we the people are finally seeing a need to swing back into the middle and compromise on shit again. I'm crossing my fingers anyway heh