There are reasons to colonise Venusian cloud-tops that don't exist for Earth ones (reducing xrisk, scientific discovery, etc)
Building a research base is not the same as colonizing.
Living in space long-term has lots of drawbacks, mainly to do with radiation and the lack of gravity.
Well, if we want to seriously travel in space, even in our own solar system, we will have to solve those problems anyway (in a form of radiation shielding and rotational gravity). And by solving them, we will end with a flying colony.
... Not sure.
Colonizing skies seems unrealistic because it seems to me like you would want to be able to land, rather than floating endlessly in an atmosphere rather than in a vacuum. THe main use for this seems like a fuel station as NTR rockets can use CO2 or things cracked from CO2.
Critically, Venus has no water.
Also, would a colony ship actually be long-term? Most locations in the inner solar system can be reached in under 5 years even under Hohmann orbit.
I was wondering what people thought of this paper by Geoffrey Landis on colonising Venus. In it he suggests that cloud-top Venus is one of the most benign environments in the Solar System. Temperature and gravity are similar to Earth, there's some radiation shielding and useful resources, and aerostats filled only with breathable air would float at that height. I'm no expert so can't speak to how accurate it is, but it's certainly very thought-provoking for such a short paper.