If you are Google, a multi billion company, pushing your own browser with a marketing budget in the hundreds of millions range (seriously, this was important to them, the only ad important enough to reach the front page of Google AFAIK)
- then you better make sure you make it work everwhere instead of this constant "ooops"-thing that shows that Google doesn't even do the smallest amount of testing in Firefox, or they do it deliberately.
If you can save a million or two in salaries for testers for all Docs products, for software that in most cases just works as well as in Chrome, why waste the money? Google is a company.
Automated tests can help with this, but you also need to maintain and write those in the first place.
Just trying to follow the thought process as an economist. It's likely hard to justify, especially with admins being quick at noticing these things and employees on docs products usually being receptive on bug trackers since it is a business offering.
I wouldn't blame some possible hack a tired dev implemented on a busy Thursday on a grand scheme to strip you of your freedom - in the end it's just people working there. Especially seeing that the bug was fixed after someone complained/made them aware.