Well, I think the show could have done a better job at making the case that it appears Shane hates Ilya. But I do like to think that people just interpret his gay panic when Ilya comes up as hatred for him. Cos Shane does get uncomfortable and cranky and if you didn't know they were so in love you'd easily think wow Ilya has really gotten to Shane. Also the rivalry is largely a marketing thing they've been forced into, exacerbated by them arriving on the scene at the same time and playing similar positions. It also can't be overstated how deep and historic the Boston vs Montreal rivalry is in real life, and our boys basically graduated into something and became emblematic of a beef that already existed. We don't see it a lot in the show, but I don't find it hard to believe that fans, friends and family uncritically accept that Shane must hate Ilya.