Is that true? Armed with a court order, the FBI can search a U.S. house, compel banks to turn over financial information, compel accountants to turn over records, etc. Yet people worldwide extensively use those American services.
Your example would have to include a situation in which the FBI makes copies of the keys to the house, copies of the hard-drives, etc. Then inevitably makes it embarrassingly easy for other parties to get access to those as well, permanently reducing your net security to almost zilch regardless of the outcome of the context and warrant.
And worse, in the process of gaining access to that one house and hard-drive, they simultaneously gain the potential to access millions of homes and hard-drives that have nothing to do with the warrant, and then those millions of houses and hard-drives see their net security reduced to essentially nothing.
If you have an argument, stick with it.
If Apple doesn't want to look bad complying to FBI requests, they shouldn't have put a backdoor in their software.
Whether they force Apple to also do the brute force themselves, or the FBI does the brute force, is not really the important part.
In other words, if some other party got the modified software, it wouldn't do anything. The software was asked to be device locked, which is trivial to do.
The reduced security you worry about already happened on the iPhone.