I guarantee these people were absolutely as shitty about LGBTQ+ issues before 2015, they just talked about them less frequenly around you since they didn't have to think about gay people too often. But I guarantee they were just as horrible towards gay people back then-- if not moreso, since they thought they could get away with the toxicity since no one cared-- as they are today.

Source: was woman with a ton of LGBTQ+ friends before 2014. Bigotry hasn't gotten any worse since then, just louder. (And the good news is the reason the bigots have gotten louder is because more normies are becoming tolerant or accepting of LGBTQ+ people, causing the remaining bigots to realize they're losing control of society and flip the hell out!)