Admitting that node count is irrelevant kills the biggest argument against increasing the blocksize

The number of nodes over a longer period of time is relevant. Node count as a metric used for 'debating' is irrelevant. You can't properly measure the actual number of nodes and the number can be faked. Your attempts at trolling won't work.
Nonsense. Number of non-mining nodes (call them what they are: wallets) is irrelevant to Bitcoin security.
Completely wrong. This implies that the entire network could be comprised of SPV nodes that
trust a small, centralized group (miners) regarding the validity of the blockchain. That is not a trustless system at all.
More nonsense, it
doesn't. Am assuming that your inference process works something like this:
1. You claim that the hundreds of padlocks thrown about on our lawn help secure our house.
2. I disagree, and point out that the padlocks littering our lawn add nothing to our security.
3. From this, you infer that I'm saying that our house is secure without those padlocks.
That's flawed reasoning. I've never suggested that Bitcoin is either "a trustless system" or secure, merely that non-mining nodes don't *add* anything to security.
Anyone reading can see this is a ridiculous analogy. Instead of inventing an irrelevant analogy, try proving the actual statement wrong. If "non-mining nodes [are] irrelevant to Bitcoin security," that implies either that "Bitcoin is secure with only mining nodes" or "Bitcoin is insecure no matter what."
My statement above specifically addresses the former. It is absolutely not secure with only mining nodes. The burden is on
you to prove the second statement.
The analogy is fine. Proving the negative is notoriously hard (often impossible), and yet that's exactly what you're asking of me.
Proving the positive, OTOH (that nodes *do* contribute to security), is a must. For the statement to have a defined, positive truth value, that is (because no proof != false, so you might have an "undefined," see
here).
So it would be much more appropriate for me to ask *you* to prove that nodes contribute to Bitcoin security.
Please do so.
Getting back to my analogy, you are asking me to prove that the padlocks littering the lawn don't contribute to our security. Because, if I'm unable to, they do.
At least, according to you.
I'll even help you to get your proof going. One tack might be to prove that it's economically unsound for the miners to counter "a_node_you_like" with a node of their own.
Of course the full-nodes we run are important and balance out the power.
Explain *how*.
Yes, your own coins are safe if you run a real (full node) wallet, but you do not contribute anything to the network which can't be countered by a VM instance (which could be leased by "bad" miners for a trivial sum).