It's pretty easy, for me at least, to understand why people are more connected to Brie Larson's dumb comments than the character she is portraying. And are having a hard time supporting a movie due to those comments where they may have otherwise still been somewhat enthusiastic to see it.
This is her 1st appearance in the MCU. If she was several movies in it would be easier to dismiss/ignore her ramblings. She'd be an established and perhaps loved/adored character that people liked/cared about. She is not a character yet. She is still a person with her own identity. She is not Captain Marvel, she is still just Brie Larson. An actor most people don't know or have an affinity towards. So we hang on her words much more than we would from a comment made by RDJ (who IS Iron Man), Chris Evans (who IS Captain America), Chris Hemsworth (who IS Thor), ScarJo (who IS Black Widow) and so on....
Like others said, sometimes we can forgive, sometimes we can't seem to forget.