"What is even more interesting is how this particular block only contains 468 transactions. The rest of data all relates to SW information. If it had contained 3.7MB worth of transactions, that would be quite worrisome" - why is it a bad thing
It's a clever (or not so clever) interpretation that this journalist is presenting here.
The so-called "Segwit data" already exists in all Bitcoin blocks, today (well, the "wit" part does, but not the "seg" part does not, but it's not even data, just a way of organsing the data). And always witness data always existed in Bitcoin, Satoshi made it that way, Bitcoin couldn't work without it.
"Segwit" data is simply the signatures for the transactions. The signature proves the owner of the BTC sent it, Bitcoin couldn't work without "witness data" (which just means "signatures")
The only difference in Segwit is the "Seg" part, not the "wit" part. Segwit puts the signatures in their own block, so that the signatures can't be switched to their inverse "low-S" form (a bit like how 2x2=4 and -2 x -2 = 4 also).
That's it. There is no mystery about "worrisome Segwit data" when you actually know what it is.