This used to be the case - until I talked to them last time. Definitely not a US-based CSR, and completely unwilling to help in a very frustrating situation I had done almost everything right on. I don't charge back often (first time on this card ever, after close to a decade) - so it's not like I have a flag on my account for "shitty customer" or anything.
Basically they utterly refused to chargeback, or even block future charges to a specific vendor that had been charging me monthly for a service I could not use due to moving. The vendor said their policy was I had to cancel in person, and refused to do anything else.
Amex absolutely did not have my back, and I have one of their higher-tier cards. Absolutely have been looking around at alternatives now though, after basically being told they'll let a vendor continue charging me against my will forever and there was nothing they would do about it. They said take the vendor to court.
I ended up canceling the card entirely and having it re-issued, since even changing the number on your card these days isn't enough to stop monthly recurring billing - of course that feature is for your "convenience".
All in all it was a pretty horrible experience that they resolved in the favor of a vendor that was quite obviously playing the "make cancelation super hard so we can collect monthly payments from people who continue to put it off" game - Amex literally could not have cared less one of their merchants was essentially engaging in barely-legal consumer fraud.
Utterly horrible customer service, and this was via many reps and a couple low-tier CSR managers. It's quite obvious to me why Chase and the like are eating steadily away at the once-stalwart Amex customer base. Prior to that experience I would not have remotely considered a different card due to them always being stellar whenever I needed them, and they usually went above and beyond any expectations I had for customer service. That trust built over the decades with me is now completely gone, and it's obvious they are simply yet another card issuer these days.