At least to me, someone is only "rules lawyering" when they're making bad-faith claims or willful misrepresentations of the rules. Inherent to the term and the reason it's pejorative is that the individual argues ad nauseum with the DM or table until they get what they want.
The one that comes to my mind was a thread on Twitter where someone asked Crawford about the Night Hag's Nightmare Haunting ability -- "[T]he target gains no benefit from its rest[.]" The person asked if the ability would prevent a Wizard from regaining spell slots from a long rest, because Wizard says, "You regain all expended spell slots when you finish a long rest." Then asked if the character could start another long rest, since "finish" and "benefit" are different words. And the only reason that mattered is because the game also says, "A character can't benefit from more than one long rest in a 24-hour period," and basically either way you rule the Wizard regains spell slots every 8 hours instead of every 24.
So, asking for a ruling on something you don't actually care about only so that you can take that ruling and apply it's literal meaning in a completely different context in order to get a mechanical benefit that very clearly is neither the literal wording of the rules nor the clear intent.