Thompson was certainly a good candidate for the district, which demonstrates how a lot of nuance can get lost in statements like "we need to run more centrist candidates if we want to win red districts." Each district has its own characteristics and there's no "one size fits all" candidate for red districts. Sanders cleaned up in the Plains states during the primaries, and part of the reason was that his more populist style plays well there. That doesn't mean you run a Sanders clone there, but you maybe do look for someone who can appeal in the area along similar lines and is a good cultural fit. A district in suburban Atlanta will have different requirements. People often have an understanding of a 50-state strategy as having some sort of slider that runs from "liberal" to "conservative" and you pick a candidate who fits at a point on that determined by the district's Partisan Voting Index, but that's not really how it works (and a 50-state strategy shouldn't just be about election-related decisions anyway).
Of course it goes without saying that we can't compromise on our core values. No running white supremacists to try and pick off seats.