Restraining someone else's head with both hands and kissing on the lips without consent - an action that not only disrespects physical boundaries, but also psychological and neurochemical boundaries, sounds a lot like sexual assault to me.

If it was the player's cheek or hand, then IMO your argument would make much more sense. This isn't the case here, and sexual assault includes a lot more than forced penetration.

As far as the law is concerned, it's sufficiently open ended AFAICT and leaves the definition up to the individual affected.

https://eige.europa.eu/gender-based-violence/regulatory-and-legal-framework/legal-definitions-in-the-eu/spain-sexual-assault-excl-rape?language_content_entity=en

How is it not sexual if a grown man kisses a grown woman and they are not in any way related?