Wrong on both accounts felgall, firstly Flash does have something to-do with ActiveX on the basis that the Internet Explorer flash player makes use of ActiveX (as a component) to run the flash runtime itself. Other browsers use their own implementation however the fact is that as far as IE is concerned, no ActiveX means no flash, no Silverlight or no other embedded executable libraries. Secondly you are actually wrong about IE being the only browser to make use of ActiveX, I discovered a short while ago that Google Chrome actually makes use (or can) make use of ActiveX (to a limited amount), While this is only supported in south-korea it can be enabled in other nations through a NPAPI plug-in (don't ask me exactly how but I've seen a proof of concept).
As far as I am aware, IE6 by default does have ActiveX turned on, however updates to windows may have altered the default preferences (as there were a couple of IE explicit updates which made minor tweaks for security reasons - like the Killerbits thing which resolved a patent issue with ActiveX itself). ActiveX is a technology, if it's enabled... anything can be run by default (as long as it's accepted for download and install by the user), if it's disabled it won't work at all. There's no grey area, it requires user confirmation and acceptance before any ActiveX component can install and run.