The people who make Lord Munodi's life hell are these guys, the Projectors, who believe in pursuing science and philosophy without too much regard for practical outcomes. Swift definitely seems to subscribe to that stereotype of the "ivory tower" of academic life. The projectors pay little attention to their hygiene or grooming. They're completely absorbed in their projects. But are these projects really worth this kind of concentration?
The Projectors want to melt ice into gunpowder, to use spider webs to replace silk threads, and all kinds of less than common sense ideas. They focus on the complex and abstract, which renders all of their grand plans totally useless in practice. (We assume, by the way, that the name "Projector" comes from the fact that all these guys have their own projects, with which they are totally obsessed.)
By the way, Swift doesn't let his satire of scientific life pass without yet another poke at politics in eighteenth-century England. Gulliver claims that the political Projectors go beyond funny and into sad with their madness. They go so far as to believe that government should be staffed by people who deserve their positions. Gulliver finds it so ridiculously farfetched and unlikely that government will ever be able to do its job that he won't comment on most of their projects – clearly, a bit of sarcasm on Swift's part.
Gulliver does offer these political Projectors some insight into his home country, "Tribnia" – an anagram of "Britain." He tells them that most supposed plots against the state are actually made up by informers who want to raise their own reputations. All the "proof" they find is similarly made up, but it's enough to convict innocent men. So, we can see that Gulliver's turn against the Yahoos is not completely out of the blue. All of his travels are starting to wear down his opinion of the England he attempted to defend to the Brobdingnagian King.