Tifa is a physical brawler, independent, sometimes the party leader, and personally resolves major story arcs in the plot.

When a man examines a strong female character, and solely focuses on her sexuality in a critical way, that's probably the biggest sexist and misogynistic red flag the writer could give off.

Then there's also:

Quote Originally Posted by Raistlin View Post
Tifa’s entire point in the plot is to be part of the Cloud-Tifa-Aerith love triangle
And despite the significance of her own story (the last Cetra trying to save the world), FFVII tries to make her a compelling character by… relegating her to Cloud’s love interest, creating the Cloud-Tifa-Aerith triangle.
Final Fantasy VII's developers have stated that the love triangle was written and implemented to be ambiguous, leaving it up to the player's dialogue choices to determine if one is a love interest, if Aeris is only a cherished ally, or if Tifa is just a childhood friend. Many fans have grasped onto this and commended the game for this technique.

The fact that you projected your own reductionist and sexist interpretation onto the relationship is another huge red flag.

Maybe this was unintentional, but this is the modern day equivalent of "The White Man's Burden": righteous males whose patriarchal attempts to champion defenseless women by exposing wrongdoers only reveals their own condescending attitudes and sometimes comfort issues with women who are firmly in charge of their own sexuality.

You're also confusing sexism with artistic exploitation. Sexism is the belief in the superiority of one's gender. Yes, Tifa's outfit and the slapping scene are incredibly gratuitous, but that doesn't stop her from resolving conflicts and even doing something the main character cannot, when she exhibits emotional superiority over Cloud during his consciousness story sequence.