Read the thread.
Generally, the reason to oppose expansion is due to their being more schools which can vote, thus making a vote to dissolve the ACC harder to win by majority vote. With 15 schools, you need 8 votes to dissolve the ACC. With 18 schools, you need 10 votes to dissolve the ACC.
Frenk favors expansion, Rad does not. Frenk gets to cast Miami's vote.
Generally, the only "good" reason to be in favor of expansion is kindness and helpfulness towards whatever teams remain in the ACC, so that the ACC does not dip below 15 teams, which would allow ESPN to renegotiate an even LOWER below-market payout to the ACC.