@awemany
To a degree what is tripping up small block adherents is the "magic" (i.e., the "invisible hand") of the market, the way people react dynamically to incentives.
As has been harped on in this thread for years, there is a strong tendency for people to extrapolate scenarios out deterministically without regard to how the incentives of all the actors involved change dynamically as the scenario unfolds. In that case it's a simple instance of greedy reductionism, where one looks at only one or two moving parts in isolation within a system that has many moving parts, and then draws conclusions as if the other moving parts didn't exist or couldn't move on their own. Or as Nick Szabo might say, they get lost examining the small game and end up ignoring the large game.
More sophisticated small block adherents perhaps understand that incentives change dynamically and therefore would
likely thwart a lot of these attacks, yet they still object because they don't want to rely on incentives and the market. This seems especially true when dealing with software, because the security optimizer's (e.g., Gmax's) instinct is to make everything watertight through code alone. In most software design, say for a website, if they didn't make it perfectly watertight, they failed. That seems to be the mindset they are carrying into Bitcoin. Probabilities and "market forces" that they as software engineers have little fluency in are considered too nebulous for the security of a billion+ dollar system.
Of course this logic is already out the window in Bitcoin, because the entire system only works because of incentives and probabilities. A large class of small block adherents' objections (of the form "miners might collude to...") just boil back down to something equivalent to the risk of a 51% attack.
Adding to this is the semantic blur of fuzzy language or over-simplified conceptions, such as viewing mining pool operators as commanding an army of drone miners without their own free will, and ill-defined notions of "consensus," "the network," and "Bitcoin" itself as these are dynamically changing in definition during various scenarios.
To have people understand these concepts will likely require visuals and even animations to show how situations change dynamically as these attack scenarios play out.
However, they are also missing the basic belief that the market finds ways of working things out that no central planner can piece together in advance (so neither can we as we try to analyze the security of the system to make it airtight, so if we aim for perfection we will never be satisfied and will be eternally ultraconservative even as competing systems threaten to take over). That belief only comes from looking at many examples in economics, which is mostly an alien field to the Blockstreamers at least, judging from how often I have ever seen them make any economic insights. Rather any economic aspects tend to be ignored or touched on in the most superficial and naïve manner.
Ultimately, although it may not be true in the blocksize situation, there could easily be a security situation where there is simply no way for us humans to be 100% sure that the incentives will play out in an acceptable way. Then we have to decide whether to take the risk and implement the change in Bitcoin or let a spinoff (or perhaps a sidechain or altcoin) experiment with it first. Conservatism to the bitter end is not an option the market will allow. If the Core devs want to try the market, they should learn to enjoy the final days of their power.
TL;DR: The illusory attack vectors are thought up endlessly because of lack of understanding of the "invisible hand" of the market and due to sloppy language about dynamically changing situations. The solution will ultimately be to help people understand more of the big picture through visual aids, clearly worded arguments, and general economic training. Ultimately, risk cannot be avoided, nor can it even be minimized within Bitcoin itself due to competition (however, the damage is limited to having to have spinoffs; investor value in the Ledger is preserved).
