It wasn’t the tv, as some commenters seem to believe. It was the trial of Oscar Wilde. Before that men used to have affectionate gestures with their male peers, they could be walking arm in arm in Hyde park and express their friendship verbally with phrases we would find unusual. The Wilde trial was a very public scandal and it marked the public’s perception of potentially punishable behavior between men, AND instilled the fear of being perceived as homosexual and socially shunned for otherwise common gestures. As an aside, the judge in the case said something to the tune of Wilde’s being the most horrible and disgusting trial he had sat on - that after judging on a child murder a couple of weeks before.

That being said, in the particular examples you are giving: Steerforth has a very relaxed approach to social norms in general and a very nonchalant way of addressing most people in his life. And Mr. Peggoty in my opinion has a fatherly feelings towards David, so that would explain why he would have an affectionate demeanor. Plus he is usually a non-emotional man, but is overcome with emotion he can’t control in his quest for Emily.