Indeed. To add to this - first to develop or not, Leibniz published first, and Newton's shameless unfounded accusations against him cannot be reasonably defended. I don't see any pro-Newton arguments in this situation besides "tribal obligations" that you mention.

In the realm of calculus Leibniz is far more influential - his notation, for instance, is so superior that English mathematicians rejecting it arguably led to the stagnation of the field in England. And of course it is far more prevalent today.