For the ones who are pro-DRM, that is probably true; the ones who realise that trying to do that is as futile as forcing one to sit in front of the TV during the adverts, probably not.
Userscripts and userstyles are very popular, and I see no particularly large backlash against them.
It's not as simple as that though. It's perfectly acceptable to want to have control over how your site is presented while still allowing your data to be accessible. If I spent a lot of time on my site UI, I wouldn't want some third party tweaking it, when that may mean I make changes to my front-end and some percentage of users break which I have no real control over. This remains true whether I replicate every capability in an open REST interface or not.
Userscripts and userstyles are very popular, and I see no particularly large backlash against them.