They suck because instead of buying the rights to the bricks they outright stole the design, the packaging and the marketing materials from the original inventor.

And then they sued the pants of everybody that tried to do the same thing to them.

That's a simplification of the Kiddicraft story.

Yes, it was a shame. After Lego lost in court (to Hilary Page's heirs I think by then) I believe they finally atoned for that.

Still, Lego didn't just sell the Kiddicraft brick unmodified. Lego patented the tubes inside, which gave it superior clutch power. (I have a lot of 2x4 bricks with "Pat Pend" molded on them!)

As I've heard it, Ole Kirk Christiansen had seen Hilary Page's brick as a sample from a molding machine vendor. Lego previously made wooden toys (until his son Godtfred allegedly set the factory on fire) and was casting about for what production to invest in for the future.

The Kiddicraft brick was a little rectangular box, no tubes inside. A lot of brick toys came out in the 60s that were little shells with varying clutch power.

For a museum of the many brick toys, go to https://www.architoys.net

In particular, Betta Bilda, Block City, American Bricks.