That is not really what she was thinking.
She saw that as someone riding the coattails of genius, the key difference of that person and the general studies class was she took all the credit for their work as the class put a team effort. And thats the key difference.
Its not about being a waste because she saw then putting the effort even with a genius helping then instead of just relying on them and take the credit, that victory was deserved due to their combined effort.
And when did she "saw them putting in the effort "?
When she sabotaged their rehearsal?
Or when she sabotaged their schedule?
Or when she deliberately removed their trainers?
Or when she sabotaged their venue?
Or when she last minute hide their whole presentation and send them to the back of the school?
Matter of fact she didn't even show up even once to see their play she wrote them off as failure and called it a day
So you must be talking about when she got the report and read the numbers saying that people voted for the gen-ed play which she spend the whole arc going literally out of her way to ruin, till the very day of the festival?
Or maybe... it is when she figured that if she messed with the numbers people could just check the polls and then all her miss management would come out to light risking her newly appointed position, so she decided to just leave it as they were
Because she never "saw them putting in the effort", from start to finish she dismissed and looked down on them
This is just the author making a rushed attempt at trying to redeem her character, by having her not act like the absolute petty scumbag she has been for the whole arc, to the point that even her own assistant comments "wow that's weird after all the crap you did to fuck over those kids, you didn't manipulate the results? I guess we have integrity now huh? Weird I guess we are just regular scumbags rather than absolute scumbags, had you pinned all wrong"