Please explain to me the system of who gets to suddenly stop a city from changing, and when? Your attitude is based on emotion and illogic. So if I'm talking about South Boston, where it is white Irish Americans being booted out by a much more racially diverse professional class, am I bigoted against whites?
Again, you have an emotional argument and nothing else. Take that same argument, apply it at a national level, and you are in anti immigration territory. If Trump ran for mayor of Seattle and said he'd build a wall to keep newcomers out, it would help your agenda.