How do you know it's 20%?

How many individuals are actually running those Knots nodes?

If it's relatively few individuals... running lots of nodes does it matter? Are those individuals actually using those nodes???

How do we know it's not Knots nodes in a datacenter, or in the cloud? If thousands of nodes are running but there is no 'wallet' connected to them, if they are not broadcasting transactions much less being used to 'verify' users transactions...

What is their purpose?

Maybe the thousands of Core nodes are a sibyl attack. Maybe the Knots nodes are who knows -

My perspective (and that of others) is that the only way to know is by looking at fees, and at the users paying fees because the rest is pretend it is all a smokescreen.

The overwhelming vast majority of the criticism I have heard directed at Core in my opinion hasn't been ethically sound, technically sound or economically sound... I have listened to Mechanic's arguments including the "debate" between Core and Knots among Peter and Mechanic and Shinobi and others...

The 'Knots' side just doesn't make any sense to me. And I believe that the "20%" metric is extremely dubious. If simply 'spinning up lots of nodes' would have a meaningful impact on the types of transactions on the network... then a government or business could easily attack the network by doing just that and Bitcoin isn't that fragile.

And I don't think that 'ignoring' certain transactions (which is what Knots does) is the answer.