Depends on the behavior and even the consequences are not as "clear" as you make it sound because reactions to behavior can be rather subjective. Context actually matters even tho it's too often ignored these days in favor of generating drama.

It's a factor way too often ignored with this issue: If "hurting people's feelings" will become a crime, then we will see no end of regulating "undesired behaviors" because people get their feelings hurt in the most subjective and unintended ways [0].

So much about "obvious examples of racism".

[0] http://thedmonline.com/greek-life-retreat-ends-abruptly-bias...

Redlining. School segregation. Unequal economic opportunity. Disproportionate use of force in encounters with police. You get the picture. These are all negative effects of racism.

there are countless facets to tribalism, and racism doesn't have to be one of them. But in any case my point is more general in nature and not about tribalism.

It's really hard for me to see how you can treat "genetically similar tribes" and races as unrelated concepts.

The concept of races and racism are completely orthogonal.

Well, that isn't really true, since the conception of what races exist and who belongs to which shows wide cultural variation.

More to the point, though, racism is an obvious manifestation of the kind of tribalism I think we are talking about and I don't think it's really controversial to argue that it is harmful at least to the marginalized groups. I'd personally even go further and say it harms all parties involved.