You bring up a good point here. I'd add too that the loose use of the term racist is also harmful to those who actually do experience real racism. I'll take an example:
When I was a teenager and working in a restaurant, one black employee was quite lazy. After a while, the manager gave him a two-week warning to smarten up, and suddenly the employees started telling everyone how the manager was racist.
The manager, worried that he might have had some hidden bias, decided wisely enough to ask the rest of us whether it was just his imagination or if this employee was in fact not puling his weight. He had offered plenty of training to the employee, had helped him along, and we'd all seen this. It still hadn't worked. So of course we'd all backed the employer and the employee got fired.
Years later though, I'd come across real racism against blacks. One man who was lied to about a job no longer being available to him even though it was available to his white friend. And another person lied to about an apartment no longer being available even though it was offered to me the same day after my friend, suspicious, asked me to check it out.
The problem though is that those who abuse the term make it less likely that we'll take real cases seriously. It's like the story of the boy who cried wolf. Ideally, we should reserve the term for when it clearly applies, otherwise eventually when racism does rear its ugly head, fewer people will believe it, with the victim of real racism suffering even more
