Okay, after navigating on the website a bit, I found this
dashboard.
We can clearly see that .onion percentage did increase from ~20% to ~50% in the last year, but that's by no means a
massive jump by someone
attacking or
trying to mess with the network, more so steady growth over the period of a full year.
It can definitely be explained by the advent and popularization of 'nodes in a box', as DaveF suggests, which in most cases come with Tor configured by default. Also simply by better guides, updates to Bitcoin Core itself and similar.
Interestingly, the number of IPv4 nodes stayed roughly the same, dropping from ~7000 nodes to ~6000 nodes, while the total number of nodes has increased a lot. It is possible that simply tons of 'node in box' with Tor by default, joined the network
[over time...].
I highly suspect if you run a node that has both IPv4
and Tor connectivity, it counts twice, so people might also just be activating Tor on their existing nodes little by little, with some of them even closing their IPv4 port (hence the declining number in that node count).
Just theorizing, but
TL;DR: MagicByt3 here somehow claims there is some massive change, something suspicious that could come from an attack on the Bitcoin network, while it just has been growing over the last year little by little...