I have been trying to describe when people say or do something or hold an opinion where it seems like they haven't spent much or almost any time thinking deeply about it, thinking it through, turning it over in their mind, looking at it from different angles, debating different aspects, analysing possible contradictions, considering if everything adds up, deepening their justification for their stance, etc.
I feel like there is a word out there for it but I can't think of it.
It's not "thoughtless" because this has a too general implication of "you are stupid", but I want to emphasise very precisely, "you didn't contemplate, you didn't think about it actively and rigorously".
I can only think of "uncontemplated", "unconsidered" or "unanalysed" at the moment and it sounds a bit awkward and it's not in common usage. I don't like "undeveloped" because it sounds haughty and presumptuous in a way I don't mean, sort of like "Oh, if only you knew the true theory like I do, once you get to my level, etc." "Rash" is roughly the idea but it focuses too much on sort of emotionally impulsive actions, so I wouldn't use it.