It is abnormal for a free software project to have an EULA (i.e. a contract that one must agree to in order to install and use the software). This particular EULA does not seem to be as onerous as most but it may still place substantial restrictions on use.
The acceptable use policy, for example, covers much more than just crime (including a prohibition on “graphic depictions of sexuality or violence”). However, it also specifically refers to “Mozilla services” so one could argue that it doesn’t apply to normal usage of Firefox; however, the Firefox EULA also specifically claims it does. Is Firefox itself a Mozilla service? I would assume not under the usually understood definition of such, but it’s not really clarified.
It’s far easier to use something unburdened by an EULA, so I’m typing this from Librewolf.
Yeah I am unconvinced of this line of thought. If I use (say) Kate Editor to edit a document, do the developers of Kate need a license to the content of that document in order to save it to my desktop? Since the text content is stored in a Qt widget does Qt also need such a license? Linux itself carries the data from the application to the disk, do the Linux developers (all of them?) also need a license?