They're not like us, they don't know or care what user agents are. The only thing that matters to them is control. To them, the idea that someone might do something they didn't approve of is an atrocity that must be combated at all costs. They actually think that browsers are glorified passive content consumption platforms where they get to set the rules and it's take it or leave it. Even something as basic as user scripts is an affront to them because it means the user is not a passive consumer anymore.