No, if he's going into "Guardians of the Galaxy" mode then he's going to do it properly.
In fact, it's a good thing
@Pieter Boelen encouraged me to do this because I found a bug.
See the line where you say "Tell me about Philipsburg."? Originally that was "Tell me about .". "philipsburg citizen_dialog.h", like most if not all dialog text files, uses placeholders for the town name. That way, if the town changes name due to period or due to the player conquering and renaming it, dialogs will show the correct name. But not if the placeholder is "#Philipsburg#", which it is in "philipsburg citizen_dialog.h". It should, of course, be "#sPhilipsburg#". So I've replaced it both in "philipsburg citizen_dialog.h" and in Adam Groot's personal variant. (Hardly anyone goes to Philipsburg, and when they do, it's probably on quest business, not to chat to residents. At least, I'm guessing that's why nobody ever reported this bug before. So not many people are likely to see "I am Groot", which is why it may as well be drastic.)
Adam Groot now says "I am Groot" in
all his dialog options. You might not be able to figure out what he means but your character does, so if you ask him for directions to, say, the tavern, he says "I am Groot" and the fast-travel to the tavern is unlocked anyway.
When you get fed up with this, there's a way out:
It's going to cost you a bottle of rum, which you need to have in your possession for this option to be available. If you haven't looted one from somewhere, it may be available for sale in Nevis brothel and it's definitely for sale in one of Cartagena's taverns. The one furthest away from Cartagena port, which is probably the port furthest away from Philipsburg. I didn't plan it that way, but it does add to the amusement value.