ALL companies are aggressive in litigating against anyone who they feel borrows their ideas via intellectual property laws. It's basically REQUIRED (by those same intellectual property laws) to maintain your 'intellectual property'.
Now, one could argue that there shouldn't be such laws or that they should be shaped differently, but that's a different discussion, in some ways.
It's only required for trademarks. Copyrights and patents don't require defending every case to maintain ownership.
Perversely it might actually be a good thing if you did have to for patents as it would force trolls into the open early on (ie before their claims run into the millions).
This is only partially true. You are 'strongly encouraged' to enforce your patent violations, for after a period of years (6) they basically become unenforceable. This is to prevent things like 'patent bombs'.
In practice it doesn't always work this way ( see patent trolls ) but it can be a BIG issue for people looking to enforce their patents.
No, that ALSO applies to patents, though the term is actually 6 years rather than the standard 3. Your 'confused' comment is a good example of why the FSF should encourage educating ones-self instead of trying to play semantic games with the english language.
But that only limits the time period for which damages may be claimed - it does not forfeit the ability to claim damages altogether, which is what may happen with trademarks; that's a pretty significant difference.
Ok, that is an interesting aspect of US patent law I wasn't familiar with. But this doesn't look like a universal property of patents, more likely it's specific to the US?
Now, one could argue that there shouldn't be such laws or that they should be shaped differently, but that's a different discussion, in some ways.