I've gotten the same thing and it definitely annoyed me to no end. It is however the case that the cabbies in LV are getting screwed over by their board and essentially honest cabbies are losing out on prime spots/fares/pay owing to the way the schedule is devised. It's made up, according to 'angry cabbies', based on who makes the most money - and supposedly these are cabbies who take tourists on the most expensive routes, roll the meters, etc. I don't know if this is uniquely common to LV, but it's certainly the only place I've ever been (lived outside of NYC and in New Orleans) where cabbies will be openly hostile to their passengers. This is a link to a blog of one such 'angry cabbie' -
http://blog.vegastaxidriver.com/.
Anyway, it relates to the fact that I guess cabbies get squeezed on the fares, plus the large number of cabs, on top of the poor allocation of said cabs and general stupidity by managment. Drives me nuts, but understand their position.