I can't argue with this
I really can't argue with this. Republic has a new product that they're still testing. If they're going to sort out the bugs that doubtless still exist, they need to know what software is and isn't running on their phones. Some people will say that, as long as what they mod doesn't affect the actual cell service, then there shouldn't be a problem. In theory, that's true, but it's impossible to know that a particular mod won't cause problems, even if it doesn't look like it should. Plus, people may not always be completely honest about what they've changed on their devices. For instance, if someone has spotty wi-fi, they might prefer that their phone be on the cell network as much as possible, and so they might find a way to accomplish that. Now the Republic techs are left to wonder why that particular device is hanging onto the cell signal when it shouldn't, and the user isn't likely to be entirely candid about what they've done, so Republic is left trying to run down a bug that doesn't really exist.
As for any software that Republic has installed, I think that, as long as it's subsidizing the service AND it isn't collecting personal information without complete disclosure of what it's doing, then it ought to be left alone. After all, Republic seems to be offering something that's a good value. If people don't want the service, then don't sign up for it.
Agreed, I use custom roms almost exclusively on my phones and while they can be just as stable as stock roms, they can also be buggy as hell and you never know what you may break.
Things that don't seem related often wind up breaking.
It really depends on the skill of the person developing the custom rom and the maturity of the custom rom, even very good developers release roms with fairly big bugs in them at first.
Custom roms don't normally get tested very much before release, they are kind of a long open beta themselves.