This is normal, and I don’t think it’s racist.

It's a sign of people with an extremely small bubble; it's not hard to understand other accents. It requires only a little consideration and acclimatisation.

It's not inherently racist, just very lazy, but it can quickly lead to racism.

English has a wide variety of accents, expose yourself enough and its probably healthy for your brain. I used to not be able to understand different American accents and I'm from the Midwest. Context and patience is king.

Neither did I. It is interesting to know that it can absolutely be trained out of you.