"This "gentleman" was feeding marmots from a bag of chips. My wife asked him to please not do that because it would create a problem for the marmots and all future visitors to this place. When he told her "that is non of your f..ing business", she asked him politely to please watch his language a little around these little girls. He then went into a rampage with many f-words..."
A good deal of the people tend to react really bad when their ignorance is pointed out to them, especially when it makes them look like a dufus in front of their friends. To stop myself from reliving the heated encounter over the next few days, I try and have sympathy for their situation. Like there they are, out with their buddies playing the role of the wilderness guide and getting a lot of pride from it. Then I come along and poke holes in that persona by explaining that they really shouldn't be doing something. Helps to, when before saying something, I anticipate the bad reaction I'm going to likely get when injuring somebodies ego.
Kudos to your wife for bothering, as the guy probably just wasn't thinking about what he was doing and the moment she said something he realized it was extremely irresponsible, but just couldn't take looking stupid with others around to witness it.
I feel really bad for the people that try and tell others to stay out of the water above falls, and then have to watch them get swept over and die, all because it is "none of their f..ing business".