The intellectual hobos would definitely save the works of Hitler and any other tyrant in the historical record. The last thing they want to do is forget the past, and then ignorantly allow someone like Hitler to come to power again. It is not to honor Hitler that they would keep his works. It is to remember his twisted thinking and to never forget his place in history and in particular, the Holocaust. There is a group, even to this day, who shockingly deny that the Holocaust actually occurred. Their belief is born out of Antisemitism: ignorant thinking. So, it is an ethical responsibility to pass on the truth of historical events: anything from a tragic event like the Holocaust to all the more pleasant events in history. The hobos wouldn't keep Mein Kampf because it is great literature. They would keep it to have a case study of a tyrant. The idea is to learn from the past and to prevent such a tyrant from gaining any power in the future.
The censorship of ideas, good or bad, is what led to the socially irresponsible and ignorant society that Montag eventually rebels against. This society is so ignorant that the notion that firemen used to "put out" fires seems ridiculous. Beatty explains to Montag that the best way to keep this thoughtless, ignorant society happy is to keep them happy and ignorant of anything they might find unpleasant:
Coloured people don't like Little Black Sambo. Burn it. White people don't feel good about Uncle Tom's Cabin. Burn it. Someone's written a book on tobacco and cancer of the lungs? The cigarette people are weeping? Bum the book. Serenity, Montag. Peace, Montag. Take your fight outside. Better yet, into the incinerator. Funerals are unhappy and pagan? Eliminate them, too.
So, as unpopular or as evil as Hitler's work might be, it would actually be irresponsible to start a trend where/when we censor things that make people uncomfortable. We need to remember the evil and good parts of our history. Start eliminating works like Uncle Tom's Cabin and Mein Kampf and there is the danger that people will start to forget about slavery or the Holocaust. An ignorant society will not be intellectually capable of recognizing tyranny or oppression if they have no memory of lessons learned from the past.