As a coli breh who is on his way home from Brazil right now, I can tell you the main reasons the passport gang travel to those three fave destinations have to do first and foremost with legality. All the reasons are already mentioned in this thread. It's not more complicated than that.
Brazil probably has, IMO, the 2nd most beautiful women in the world (in a matter of speaking). I think Venezuelan women have the absolute most gorgeous faces but they, in general, lack bodies. Brazilian women have both physical beauty and sculpted bodies hand made from heaven. Again, its not ALL brazilians, use common sense.
Colombia - I makde 3-4 trips a year on the regular.
DR - maybe once a year now for me. I personally find DR women too Americanized and hardcore.
In Brazil as and in Colombia, prostitution is legal and regulated in Col. Brazil is a free for all. Pimping is not tolerated at all in either place and you will do some heavy jail time. And oh lord, never, ever, never never, ever, never never, ever, never never, ever, never never, ever, never engaged with someone who looks like she could be a minor. Just don't !!!
When I am in Colombia and Brazil, I definitely go and visit casas/termas (br). That's where women legally work as prostitute. There is no stigma like in the US/ and some Euro countries to women selling sex a a service. A lot of women with legit careers sell sex on the side to make extra bucks. It's perfectly fine and legal and accepted. Its the culture. These women do not need you to be their moral high ground, period.
Just spent 8 days in Brazil. I visited a terma (casas) once and a strip club on 2 separate nights. All visits ended with getting laid for a fee. The other times, I just chilled with local girls I met on Tinder or cupid for a day or two each. I had a rental and we drove around, they showed me their favorite places and took pictures, had dinner, did some activities like parasailing, 4x4 tours etc They took tons and tons of pics for the IG pages and guess what I didnt give any direct money. They knew they wanted to make sure I was pleased too. they did not disappoint.
Again, there is not stigma to sex in these places. Copacabana is full thong assed women all day with huge natural asses and fake ones too. No once cares. They are women working on the beach offering their svces in plain view, no one cares.
Brazilian women are hot and passionate and they fukin love sex, prob more than most men. These chics are on fire.
Sorry for the long post, i am at the airport with much time in my hands.
I cant get a pic posted for some reason but here's the link for my official passport stamp out of Br: