A "flippant remark" means a comment or response that is made casually or without serious thought or respect. It's often seen as lacking seriousness or being disrespectful. Full definition
A woman makes flippant remarks about leaving her husband if he doesn't get back to working for a living. (parentpreviews.com)
Second, it was a rather flippant remark, not meant to be taken seriously. (religion.blogs.cnn.com)
For this reason, I find Paul J. Griffiths» somewhat flippant remark that the analogy of the Good Samaritan applies «not at all [to] the U.S. Army» to be ill thought out. (firstthings.com)