I have learned that game piracy is considered off-topic in Arqade.
Does it also count as off-topic if we ask how to get free robux in roblox?
Asking for users to give you free robux (or for that matter, any in-game currency) is definitely off-topic. We're a site about getting expert answers to gaming questions, rather than about requests for resources (free or otherwise).
However, if Robux is a currency that can be earned in-game, then asking for ways to earn robux (using tricks or methods that are easy/quick/repeatable etc) - that sort of question would be on-topic.