First, this is a terrible analogy. Changes to the Bitcoin protocol should not be made in any way similar to the way presidents are elected. In any case, presidents can be (and often are) elected by a plurality, not a majority. A candidate with less than 50% of the vote won in 1992, 1996 and 2000.
I don't have an interest in BlockStream at all. I think the threat of a hard fork with only approximately 75% of the mining power and with a significant portion of the community against it is very dangerous. I started to write that I have a "deep interest" in Bitcoin, but I'm not sure that's true anymore. What I see happening now makes me tend to think the Bitcoin "community" isn't so different from other communities. People split into tribes, shout at each other, call each other names, and then celebrate their victories or console themselves with their losses. I suppose I was too optimistic to think a cryptocurrency community would be different. One reason I thought it was different was that I had the impression that the fundamental rules were fixed and no longer in the hands of fallible humans. It turns out this isn't true.
Regarding BlockStream, it's clear that much of the Bitcoin community finds them controversial. It's also clear that they're doing some groundbreaking research, and that this research would apply to other cryptocurrencies than Bitcoin. Perhaps BlockStream should just implement their ideas for Litecoin and leave it to those in control of XT to develop what Bitcoin is to become. Would you find that preferable to the current situation?
Present a logical argument against increasing the block size or admit you are harming Bitcoin by perpetuating this split!
I'm not sure what you would consider a "logical argument." As a logician, I'm inclined to interpret it literally, but I suspect it's not what you intended. A logical argument is a deduction starting from some axioms and leading to a conclusion. In your post you actually referenced two different possible conclusions: XT should be opposed. vs. The block size should not be increased. Now, it should be easier to give a logical argument for why XT should be opposed, since if someone already shows the block size should not be increased, then it logically follows that XT should be opposed.
Of course, it's impossible to conclude that XT should either be opposed, supported or even ignored unless we start from some axioms. This gets to the root of the issue. Different people have different fundamental beliefs about what Bitcoin is and what it should be.
Often I've seen the argument that Bitcoin should be censorship-resistant way for individuals to control their finances free from government control. We could take this as an axiom. Another axiom could be that for a cryptocurrency to remain censorship-resistant it is vital that it can be safely run behind Tor. Finally, we could add an axiom that states that some of the new code in Bitcoin XT makes it difficult to run Bitcoin XT safely behind Tor. With axioms like these, and possibly some more, we could chain together a logical argument ending with "XT should be opposed." I'll flesh out the details of the argument upon demand.
Now, of course, you could say it isn't a logical argument because you don't accept one or more of the axioms, but this is not a criticism of the argument. It's a criticism of the axioms. I could give many logical arguments (and for a reasonable donation I'd be willing to formalize them), but you could always reject the conclusion by rejecting some axioms used. That's just how logic works.
You have certain axioms of your own that I've seen expressed in many places. An assertion that is often made by supporters of XT is that BlockStream wants to keep the block size limit in 1MB so they can make more profit. Using this as an axiom, and probably a few other axioms, one could probably logically argue that BlockStream has nefarious motives for opposing XT. However, even this wouldn't logically rule out the possibility that BlockStream (or, more precisely, the employees of BlockStream) have both nefarious and intellectually pure motives for opposing XT. The possibilities aren't exclusive. Maybe one could argue about whether their primary motive is nefarious or pure, as presumably there is only one primary motive. Logic forces one to be annoyingly precise.
It's natural when people get into these kind of tribal arguments that statements such as "XT should be opposed" or "XT should be supported" themselves rise to the level of axioms, or, fundamental beliefs. Once that happens, any statements that would contradict the fundamental belief are immediately rejected. At that point it's impossible to have a consistent set of beliefs/axioms that would imply the opposing statement. In other words, eventually people are so sure of their position that it's impossible to convince them of anything contrary to it. If that's what's happened here, then every logical argument someone could give which concludes "XT should be opposed" would necessarily have at least one axiom you would reject. Your only other choices would be to change your mind about the conclusion or ignore the argument. Realistically, ignoring arguments is typically what people do in these situations.
Thank you! That was one of the most enjoyable posts I have read on this forum for quite a long time.