No one is gonna “force“ Utah or anybody else to join the Big 12 if they don’t want to. If you get to the point of extending the invitation, you extend it, and they say yes or no. If they say yes, then any “public statements against joining the conference” are essentially null and void.
I can see what you mean about actually inviting a school that’s bad-mouthed your conference - maybe you don’t end up doing that - but if you think that school can be a benefit to your conference both financially and competitively, and the situation looks favorable, and (perhaps most importantly) that school is running out of viable options … why not invite them and put the ball in their court?
I don’t have a strong opinion either way about Utah, and there might be other more attractive options out there soon, but just because the AD said some bad things about the Big 12 recently doesn’t mean they wouldn’t be happy to be offered a lifeline if their other choices were the WAC and the MWC.