What does "the facts about themselves" mean here?

Question

Could you please let me know what "the facts about themselves" means in the following sentences:

I was in no great pains to keep in touch with England. I followed local advice for my itinerary and had no settled route, so that much of my mail never reached me, and the rest accumulated until there was more than could be read at a sitting. I used to stuff a bundle of letters into my bag and read them when I felt inclined, which was in circumstances so incongruous—swinging in my hammock, under the net, by the light of a storm-lantern; drifting down river, amidships in the canoe, with the boys astern of me lazily keeping our nose out of the bank, with the dark water keeping pace with us, in the green shade, with the great trees towering above us and the monkeys screeching in the sunlight, high overhead among the flowers on the roof of the forest; on the veranda of a hospitable ranch, where the ice and the dice clicked, and a tiger cat played with its chain on the mown grass—that they seemed voices so distant as to be meaningless; their matter passed clean through the mind, and out, leaving no mark, like the facts about themselves which fellow travelers distribute so freely in American railway trains.

• Evelyn Waugh, Brideshead Revisited, Book Three

The narrator Charles, as an architecture painter, travelled Latin America for two years in search of inspiration. He didn't particularly seek to keep in touch with his homeland, and the letters he received sounded so remote to him.

In this part, I could not grasp what "the facts about themselves" means.
Also, in order to know what "themselves" is, I looked up "fellow travelers" and found the related information on the Wikipedia, and assumed that they were communist sympathizers, but I could not be sure about that either.

I would very much appreciate your help.

Answer 1

One possible way to read this passage is that Charles does not pay much attention to news from home, no more than he pays to the nattering chatter of other passengers on the train in America. Some people think Americans are especially given to striking up unwanted conversations with strangers on the train; in some cultures this can be regarded as a form of rudeness, an invasion of solitude and hence of privacy. Such facts about themselves as they offer ("my uncle Orley -- he came from Altoona -- was very fond of chili sauce, and said it was healthy, but he died of cancer at age 43", say) slip out of Charles's consciousness, and leave no mark on his mind.

In short: in this passage, "fellow traveller" means "a traveller sharing location with me for a period of time", not "Communist sympathizer".

Answer 2

When people find themselves in the company of others who they expect never to see again they will sometimes reveal things about themselves that they would not reveal to people they know or expect to meet again. They might blurt out that they had given a child up for adoption, or confess that they were an alcoholic, for example. It is indicative of the character's (Waugh's?) arrogance that he is dismissive of this type of communication which is not peculiarly American.