It's a bit deeper than that, and I was in your position until others provided education. RCS as a standard, like SMS/MMS currently are, was abandoned by the carriers. The RCS you see today is Google's proprietary solution, which ostensibly Google will profit from in some way or another. The distaste many have seems to be 1) will there be privacy issues around this? 2) You still have to download Google's app instead of it working universally like SMS/MMS do. 3) Google has a penchant for going full steam on projects, then abandoning them. The RCS the carriers support is Google's Jibe version, which is different than what a "universal" RCS implementation would be, the one the carriers all dropped in favor of Google's implementation.
I agree with you. My biggest issue is the last sentence in post 548.