
I think the word Classic was a reference to when he/she started reading yaoi. Since the said person started reading Yaoi in 2013 (I think), and this manga was the beginning of their adventures in "Yaoi" i guess i could see why they reference this as a classic.
Although the only think i see wrong with the original post is the word "Yaoi" since this back in 2013 wasn't considered a yaoi. So it should have been the beginning of my adventures in BL. In 2015, did they finally continue this story and added a sex scene lol

I am very picky with my usage of words so don't mind me, i usually correct anyone who writes "Yaoi" instead of "Shounen-Ai" so i tend to be very annoying but it's just my habit. But i understood what you meant by it.

Oh you're new to the BL world?! Amazing! yeah the word 'classic' was kinda odd to me because this manga is fairly new hahah (like when people talk about the classics they usually refer to gravitation, haru wa daiteita, bronze, etc or the newer classics like junjou romantica or honto yajuu)
But yeah this manga is one of my favourite ones, it's amazing and I love that it's ongoing! (also if you like this kind of storylines you should check my lists to find nice bl manga! i don't read things with rape so if you're new to bl you might want to check them out!)

http://www.mangago.zone/home/mangalist/47430/ that's my 'Best BL Manga' list
and this one http://www.mangago.zone/home/mangalist/48555/ is my light read one, this one has shortest and fluffier manga and the other one has like suuuper good ones!
this brings back memories. this is the first yaoi i've read that i really really loved, one of the classics for me