The real reason why Ryanair landings are firm is the aircraft they fly: the 737-800 has a very efficient wing at low (landing) weight so the aircraft has a tendency to float above the runway when landing and not touch down on the runway easily. The aircraft is very long relative to the undercarriage length, so you cannot flare (pull nose up) a lot to put the aircraft down on the runway very softly. If you flare sharply the tail will hit the ground, damage the aircraft, and make the pilot very unpopular. Ryanair achieves its safety mostly by having very strict standard procedures and enforcing them very tightly, including landing in the touchdown zone with the correct approach procedure. Putting these together means that Ryanair pilots put the aircraft down firmly in the touchdown zone every time to make sure it brakes properly and everything remains safe. That is a good thing.
There’s a difference between a hard landing and an assertive landing. Conditions determine this difference. Half of these were assertive. Come in with energy, plant it on the ground, wipe your brow. If you know flight, you know how to judge the approach angle.
I ess told that naval aviators make rough landings and Air Force pilots made smoother landings. The reasoning was that landing on aircraft carriers the pilots were forced to make rougher landings.
I was on an plane once and we were landing at OIA (O'hare International Airport) and the pilot decided to literally Hit the wheels on the runway and there was a loud thud