I mean, as your other comment points out, it is still very much an "active" US military vessel.

LEGO often catches flak for the increased presence of weapons in their sets (like the entire Star Wars line) and many argue that is at odds with their ethos of not producing sets that promote violence. I agree that it is sometimes hypocritical. Their defense is the "weapon-like" elements are in fantasy settings and not real-life scenarios that promote violence. Which a military ship (even as a glorified museum) would be counter to.

This is all besides the initial point that the USS Constitution isn't anything like the Space Shuttle in terms of military use. One carried military cargo at times while the other actually engaged in battles.