Strong disagree. There is an antipattern I've seen across the entire industry, including big companies that should know better, where UI work is undervalued and considered "not as complex" or "simpler". I have fought with promo committees who didn't want to promote people because they assumed the UI work was "easy". All of the people making these claims had worked exclusively in backend for a long time and all of the should have to go take an IC role putting up with the hell that is modern frontend development. Only then will I give any credence to how difficult they think UI work is.
If your argument was "because there are 10x more frontend devs fighting for the same job", that's one thing, but saying it should be done because the disciplines are different is nonsense.