"Maybe he gives off very strong ace vibes to his students, so they pine away quietly without bothering him? (I can see him appearing ace when ZYL isn't around, you know?)"

He kinda actively tries to appear more ace when ZYL is around, hahah. :D :D

But, as trobadora said, in the end I don't think there's anything that can stop students from crushing on a teacher, especially a teacher who looks like Shen Wei. :D I hope they're respectful about it, but he kinda has to know anyway? Unless he actually doesn't know because anything other than his full-time pining job is irrelevant, hmm, that IS a possibility. xD