Also kids used to play/dress up as "cowboys and Indians" I'm obviously missing something but could someone tell me why it's not offensive to dress as a cowboy but it is as an Indian? I'm so baffled by this.
White Europeans 'settled' North America. North America was already inhabited by indigenous people; predominantly Native Americans in what is now the US and First Nations people in Canada. The vast majority of indigenous peoples were killed, either directly through violence or indirectly through diseases introduced by the Europeans. In all, 90-95% of indigenous Americans were killed, leaving communities devastated. They have since been oppressed and discriminated against.
Where I am (Canada), the white folk decided that we simply couldn't abide indigenous people continuing to have their own cultures, so made a concerted to wipe out their cultural practices. Children were stolen from indigenous families and placed in government funded boarding schools, where they would be prohibited from engaging in any of their cultural practices, and be absorbed into the dominant white culture. The children were neglected, abused and thousands died.
This happened for several generations. The last of the residential schools closed in 1996. Indigenous communities continue to be deeply affected by the trauma. Much of their culture is lost forever.
'Cowboys and Indians' is a genre of white European culture, where the white folks are the goodies and the 'Indians' are the baddies. The 'Indians' are often portrayed deliberately negatively and, even when that isn't the case, as stereotypes that parody indigenous cultures (and don't attempt to be an accurate depiction).
All but wiping out a race, attempting to destroy their culture, then deciding it's fun to dress up as that race, complete with bad parodies of their sacred cultural dresses and practices, is pretty awful.
I don't see how you can compare it to a white person dressing up as a cowboy.
And if 'red indians' really are close to your heart, I'd suggest that you stop calling them 'red indians'.