The sms decision made signal go from THE messaging app on my phone to an app I only use with a very small subset of my contacts. It is infuriating that they didn't allow users to retain that functionality when it costs them nothing, and they could have disabled it by default.
I still use Signal a lot, since most people I frequently talk to use it. However, this was extremely frustrating. Having 1 messaging app for so long was incredibly nice.
Many people care about Signal, and it is okay to dislike their decision. OP didn't demand from Signal to support SMS, but they expressed their emotions about the change.
Signal is an awesome project but some of their decisions annoy many users. E.g. Signal does not allow to automatically save all pictures in the gallery. It's a privacy feature, but it's inconvenient since it forces me remember to download each image seperately.