While Google is a major pusher of RCS, the standard is owned by GSMA. The entire standard is also published and freely available. Furthermore, RCS messages are not required to use Google’s Jibe platform; other companies are free to use their own. For example, many EU carriers do not use Jibe servers. Not all RCS messages go through Google servers. Technically the standard is even open enough to use individually, but you will realistically run into road blocks setting it up yourself. In any case, please stop regurgitating this nonsense.
https://source.android.com/static/docs/core/connect/ims_single_registration_v1_1_1.pdf
https://www.gsma.com/futurenetworks/rcs/universal-profile/
https://docs.google.com/spreadsheets/d/14Ns9oV0Dh8_S5M-JHDvJ8sNHR6rpbiq2N6qZlP3g9zQ/
Why you gatekeeping ass? Also, how is the concept of a pre-sex shower unusual to you? And bidets are a thing which are used to clean up after shitting / before sex. As for the first question of “why”, well… just like most other sexual acts, it feels fucken great. No judgment if you’re not into it, but don’t hate just because you aren’t.