Now imagine this kid sees another kid. Kid B is living on the margins. This kid can't really afford to get anything super valuable until holidays. But something great happened. Kid B got super creative and MADE themselves an awesome toy. Something they thought they'd never be able to have. It's pretty patchwork and rough, but it's theirs.
Kid A is furious. Kid A is utterly indignant. Kid A doesn't have this toy! They scream and cry at Kid B about how unfair it is! Despite Kid A's room being filled with all kinds of valuable things, they're still throwing a tantrum at Kid B's gain. Annoying, right?
This is how it feels when people say All Lives Matter. This is how it feels when people say "If there's a Black Entertainment channel, why isn't there a White Entertainment channel?" This is how it feels when men tell feminists "What is feminism doing for men?" This is how it feels when people criticise marginalized groups for making safe spaces for themselves.