Let me start provocative:
Being a pilot is great. They wear nice uniforms, enter the cockpit, press some bottons, start, press some more bottons, land and that's it. Really? Partly yes (don't shout too much before reading to the end) - as long as everything is working fine.
Real life is different. An aircraft has today a lot of automatics as a result of thousands of man years of engineering - and it is getting more and more. All these automation tools make the plane easier to fly and safer to fly - as long as everything is working fine.
The pilots have to control these tools, to check weather the output of these tools (e. g. thrust level) is consistand with the actual situation. Is one of these tools inoperative - no problem, this will be flagged and other systems (including pilots) can react. But when they are still operative and produce nonsense it is getting more complicated. To realize there is a problem and to come to the right conclusions within a few seconds... that is the problem and that is why the guys in row 0 don't have to pay for their seats but are payed.
Rainboe put it perfecly into very few words some days ago: "Pilots have no right to 'rely' on automatics."
Seems he knows Tom's first principal theorem of enineering: "Only nonexistent technical equipment will not fail" (Originally: "Nur Technik, die nicht vorhanden ist, wird nicht ausfallen.") That means pilots always should expect a failure.
A last try to stop the discussion about different radalt readings:
Of course it would be possible to check the two radalt if the reading is aproximately the same. Ask Mr. Boeing or one of his enineers why they don't check for discrepancies. I'm sure they have one or more good reasons.