"I don't purchase from comapny X ever since they did Y" is a perfectly reasonable thing to say when people are talking about company X. The reasonable response to someone saying that is simply "They don't do Y anymore, they haven't done that since [date]", not "HOW DARE YOU SHARE THE REASON YOU STOPPED USING COMPANY X IF YOU HAVEN'T BEEN FOLLOWING EVERYTHING THEY'VE DONE FOR THE PAST COUPLE YEARS!"