Have you ever been to a website that won’t let you copy text? Like this page, for example? There are a few workarounds for this, especially with Firefox.
The easiest is to just click the “Reading Mode” icon in Firefox’s address bar:
This presents a simplified page with most of the ads and graphics stripped out. You can easily copy text now:
Another option uses uBlock Origin. uBlock is one of the most popular ad blocking extensions, and it’s available for Firefox, Chrome and Edge. If you don’t use uBlock already, you probably should. In Firefox you can install it by clicking the hamburger icon in the upper right corner of a Firefox window and then “Add-ons and themes” and type “uBlock Origin” in the search bar. Make sure you install uBlock Origin and not plain old uBlock or any other variant. For other browsers, just go to its extensions site\store and install it from there.