Why are these two countries freaking out?

Seriously, Venezuela and Ecuador are throwing fits because Colombia killed a rebel leader. Sure they can claim their sovereignty was violated but honestly anybody who has paid any attention to colombia can tell you that the rebels in that country are vermin of the lowest sort. It bothers me that venezuela is mobilizing troops to it's borders to "protect it's sovereignty". Who are they trying to kid? They're trying to protect TERRORISTS!!! so my question is this doesn't it seem politically foolish to take actions that clearly back murdering criminals? And why does the world let these two countries get away with these shenanagans? Shouldn't the UN step in and do something?