Safari crashing on WSJ.com
WSJ website now behaves normal
WSJ must have updated their website. I can't reproduce the huge RAM usage on the website and have not done any Safari or macOS updates. Therefore it was not an issue with Safari but with the WSJ website itself.

This is not a very technical answer but WSJ customer support is sort of correct.
I just loaded WSJ website myself and after a few seconds the RAM usage was way too high:

This will be too much for any iOS device and even for lower-speced Macs.

I can't tell you if the WSJ has made significant changes to their website the last days or if it is Apples fault. Either way I would - if its that important to you - write to both Apple and WSJ about this.