Think of the school yard situation where Nick is bullied for his leg, Tony yelling, “You walk funny!”, punches down and isolates and separates Nick from the group. Inclusion (more so, not being rejected) is strongly important to most humans.
If Nick shouts back “Tony, your straight legs are like everyone else”; it doesn’t hold much strength, power or bite. It’s because Nick is punching up. Tony remains comfortably part of the hegemonic group part of the majority with no loss of anything really.
I think this is an evolution in distinctions on this, earlier framing was that any racially insensitive comments were all collectively racism; the current framing seems to be some comments are racially insensitive and are a bit awkward while others shift power, divide and exclude; and the later is being defined as the more contemporary definition of racism.
In short if the type of slur is not biting at you it’s likely because your power or position or inclusion as “one of us”, is not at risk or in question and it’s hence much easier to brush off.
For people who fit well into the majority, much of this can be very invisible; hence so many comments from people with privilege often confirming to each other; I can’t see a problem here, I don’t feel this.