Plus, 357 sig and .40cal are both high pressure rounds. they WILL wear out your gun faster, especially if you put a lot of rounds downrange like many pros do. Its that simple.
SAAMI pressure specs that I've found are 35,000 psi for 9mm and .40S&W.
Wikipedia says 34K PSI for 9mm and 35K PSI for .40S&W, everyone else says 35K each. Even if wikipedia is right, an extra 1000 PSI and suddenly .40S&W is a high pressure round and 9mm isn't? So compared to the 21K PSI .45 ACP I suppose that 9mm must pretty much just disintegrate after the first magazine then?
.40S&W develops more ENERGY, which naturally will cause more forces to be exerted on the gun.
It also causes more forces to be exerted on your target. Which do you care more about? Make your decision. But pressure has nothing to do with it.
Conduct research, stop listening to internet talking heads giving inflammatory opinions for the purpose of getting higher youtube view counts.