People dont like flash because it takes long to load, make for slow and unresponsive ui's, consumes lots of cpu, ruins vast amounts of basic usability and is generally a bad player in the web department.

Flash is not required for reliable and interactive interface, it is needed however to deal with multimedia reliably, so when people look down for using flash, just tell them you cant do what you need to with current web standards. Looking to the future I think its pretty unarguable that people should be looking to move to web standards when they are reliably available