Never heard of it before.
I think it's rather funny.
A lot of people do tend to get way too uptight any time there was some big disaster involved. Essentially, it'll never be "ok" to make even the slightest joke about the titanic.
The truly funny thing about this is that it can never truly sink. It'll stay down as long as you hold it down, then pop back up to the surface. Even when you drain the tub the plug will still outlast the water.
I guess the real joke here is that they made a toy that's better quality than a world-famous ship. ;)