It’s relatively dismissive of the past to imply that it was not a lamented loss at the time, but it was a loss we learned of after the fact- not before it.
This is the earliest indication I can find:
https://news.ycombinator.com/item?id=12112850
That was the same day the acquisition completed.
I think the difference here is that now he thinks that a sale to Nvidia threatens Arm's business model, as now Nvidia will be deciding whether it wants to sell it's licences to it's direct competitors.
As far as ARM specifically well they have already revoked the licenses for Huawei and a few others and now there is the situation where ARM China is essentially a rogue entity being seized by the CCP.