I'm not sure how easy it is. Many die along the way, or split up families to do it. I'm not condoning it, and I don't like people coming here illegally either, but I can see why people would do it.
I don't think those coming here illegally have a great life in Mexico and just want freebies because they feel entitled. I don't buy that at all. I think they are mostly forgotten people who have nothing and no hope where they are at, thus they have nothing to lose and everything to gain. I couldn't imagine walking a family including young children through hundreds of miles with little food and water just to get some freebies.
Again, I don't like it, but I think I understand why they do it. And, I don't like that we ALLOW it to be a low risk venture for them with a big upside if they succeed in breaking our laws. That is not right.
You mention robbing a 7/11... imagine if 7/11 left their registers open, and when burglars arrived they simply said "do not take the money, it is against the law". Then, when the robbers took the money, 7/11 said "ok, you can have the money. Since you've already taken the money, have some chips and a Coke too".
Word would get out, and 7/11 would be robbed all the time. But where does the blame lie? Sure, in one hand the robbers shouldn't be doing it. But we all know human nature - if 7/11 does nothing and allows it, isn't it their own fault?