The article used that wording, "a classic risk of a race to the bottom", but it doesn't feel entirely accurate to me.
A classic example of a race to the bottom is when jurisdictions compete to attract businesses by lowering their corporation tax rates and regulations. The end result would be zero taxes and zero regulations (unless a country offered a negative tax rate or other incentives).
For censorship, though, I don't see there being a "race" between countries. Just because Austria bans defamation doesn't mean that all other countries will try to out-compete Austria by banning something even less objectionable. What would "the bottom" even be in this "race"? Banning all speech from the internet? Internet companies would simply avoid having any assets or presence in any country that tried that.
Perhaps a better analogy would be "opening the flood gates" or "a chain is only as strong as its weakest link", suggesting that the strictest set of rules would be the one that ended up being implemented.