Yes, Ryanair splits up parties if you don't pay for seats. Even when travelling with your children.

Is it mean? Definitely. Is it dumb to fly Ryanair nonetheless? Definitely...

However Ryanair has built a very profitable business off of people forgetting all of the downsides (or extra charges) when offered a cheap-looking flight or the only direct routing. This doesn't bother me because the competition helps keep fares lower on those airlines I do choose to fly with.