This is a reasonable restriction and I am surprised this restriction is coming now and not ten years ago.
Sideloading must be limited to tech savvy users only who know what they are doing.
Who says so?
I'm not picking sides, but I try to help myself understand things by visiting both sides of the arguments and there is clearly a side interested in cutting down on fraud, just as there is a side promoting freedom in their computing. Limiting sideloading seems a sort of pragmatic move, and leaving the possibility of sideloading open seems to be likewise a pragmatic move, especially if there are guardrails and warning signs everywhere, we do this in society when faced with hazardous situations.
I am very open to counterpoints here, at least if I can read them before they get too greyed out!