I don't know why one series against Missouri and one bad day at Hoover takes us from #2 or 3 to missing the top 8 myself.
I think it may have something to do with the SEC really deserving 5 of the top 8 seeds but the SEC hate is still strong
Limiting SEC teams is part of it, part of it is just that the gap is that narrow at the top, and part of it is that there is recency bias. We have looked like **** in 3 of our last 7 games. It's not like teams don't get lit up during the regular season with lopsided scores and have bad weekends, but it unfortunately matters that we have made such a strong negative impression recently, even though you could have sprinkled those games throughout our schedule and nobody would think anything of them. Hell, if we had looked like **** in one game against Missouri and one game against Bama and won each series 2-1, I don't think people would be as concerned.
But yea, that's the reason people are concerned and while I think we're a national seed regardless (mainly because I don't think the committee members are necessarily watching us, and I don't think it leaves the same bad taste if you just see a box score and are looking in the context of an entire resume), but I don't think their concerns are completely unfounded.