I'm not saying that he said college, but I'm also not saying that he didn't say college. If he did say college, he must have also bumped his mic or something because it sounds like he said something like "collid- sorority" which very much sounds like somebody who doesn't enunciate the R in "colored" or somebody who started but didn't finish the G sounds in college.
As for why he would need to clarify college sorority, the right has been demonizing college students since at least the Vietnam war protests. Educated people question authority, so they want fewer educated people to question them. That's why tuition has gone through the roof, it's why bankruptcy doesn't forgive student loans, it's why certain people have become proud of their ignorance, and it's why there's this opposition to student loan forgiveness with the framing of "taking your money to pay off their poor financial decisions". Specifying "college" while talking about sororities tickles the buzzword receptors in their viewers' zombie brains so that they can connect the dots to "thing bad because man said 'college'" because it's possible that they don't know that "sorority" already implies "college". Implicit subtleties are not their forte.
So now they're in a weird position which is admittedly pretty unimportant culture war stuff: did he say "colored" which is racist of him, or did he say "college" because he assumes that the viewers are so intellectually stunted that he has to spell out that they should be angry because buzzword. Because they don't give a shit about this, they'll handwave and say "so what" because they've already decided to support and defend who they support and defend. Fox News is their gospel, and they can only be shaken from supporting that gospel if their other gospels (trump, reagan, NRA, televangelism, etc) conflict or outright condemn it.
This won't move the needle, and some independents might think it's petty to put a lot of attention on this. It's probably best to move quickly, point to it and say "hmm, okay he either thinks you're racist or he thinks you're dumb. Both are bad. If you join us, people won't assume that you're racist or dumb. Prove it by voting for our smart, more equitable policies."
Lol I said that he's either pandering to racists by saying "colored" or pandering to morons by saying "college" and you think I'm defending a racist? Nah, he's wrong in both cases. I'm pointing out that the only defense they can claim also isn't good for them.
Maybe ask the guy sitting next to him who looked pissed off rather than the guy trying to cover his ass after the party was instructed to tone down the racism?