This is not a new phenomenon. My glory days of Lego were in the early-mid 90s, and literally every set that my friends and I were interested in were either explicitly martial or violent in a GTA-esque, drive-fast-and-crash-into-stuff way. Catapults. Castles. Dragons. Knights. Space fighters. Giant robots. Drag racers and police cars, in realish life or in space. Factions of undersea divers with monstrous submersibles at war over glittering crystals. Pirate ships, with cannons and crocodiles and angry natives, etc. Every good Lego theme set up at least two factions which were at least implicitly at odds, if not explicitly at war.

This is the shit that sells to little boys - Legos are just better army men. Ironically, the pacifistic stuff tends to sell better with the AFOLs, as witnessed by the resurgence of the line of modular town buildings, and architecture sets explicitly marketed at adults.

The more disturbing trend with Lego is the continuing rise of licensed themes that has completely gutted their product lineup. Star Wars has been a cash cow for them, but has meant that that is it for space-themed Lego sets for around 15 years now. Likewise, two of the other of the four classic System themes, Pirates and Castle, have been on ice for years, due to overlap with Tolkien and Jack Sparrow-related licensed themes.

They seemed to be trying a little harder three or four years ago, but I've not seen anything really exciting the past few years.