That is the “official” answer according to the show.
The problem is that there are different rules for factoring, and it was not clear which they were using. Many sources ignore “1”, because it always applies. Likewise, if they wanted to apply the 2 twice.
I am no math person, but I hazard to guess that it’s not 8 because 8 can be factored down into 4 and 2? I dunno. (and then 4 can be factored down to 2x2). The lowest common factor would be 2, right? (I don’t count 1). But to factor 24 and 32, it’s either 12 2s or 16 2s, OR some combo of 4 and 2.