You can talk to an extremist for any platform, and you can bring up a deficiency for that platform, and the answer you will get will be one of the following:
"Well, why would you want to do that anyway?"
"Just don't do that if it stinks."
Illustrating the point would be Apple's continued lack of support and love for mobile Flash. Any time someone says, "I need Flash on iPad," an extremist will say, "Well, Flash really isn't that great, use HTML5 instead."
Are they right? Yes. Flash is awful. But it's indicative of a lack of willingness to see things as flaws rather than a lack of things we don't want.
Step one to dealing with your platforms flaws is crucial: admit that those flaws exist. Yes, Flash on Mac OS X and Linux isn't very good. Yes, there is no Flash for iOS, and that limits some of the web that you can experience. Often there is no substitute for Flash.
This is a flaw. There is no denying that. Don't dodge the issue by trying to say, "Oh, but you didn't want that anyway." Yeah, I did. It's an issue. Let's deal with it.
Step 2. This is where we can deal with the flaws and say, "Okay, there's no Flash here. What can I do instead." HTML5 is good but still unsupported in most browsers. Or even better: what is it we are trying to do on the web that requires Flash in the first place? Would we be better served with static images or a simple video file that we download and watch in VLC?
Yes, we can get around the issue of Flash in Linux and OSX. But never forget that it is a flaw and we need to deal with it.
Linux cannot run Photoshop. This is a flaw for many people.
Linux does not have a good, standard tutorial website or system for new people to learn Linux. This is a flaw.
OSX cannot be run on anything but Macs, thanks to its EULA. This is a flaw. Windows (after XP) has remote activation DRM. This is a flaw.
Now, what do we say about these things?
"Yes, it is a flaw that Photoshop doesn't run in Linux. However, some versions run in Wine, and the GIMP is a good subsitute for people who use a limited set of its features. If this is not good enough, perhaps Linux is not for you."
Intelligent people will understand that even the things they hold most dear to their heart, and the tools they swear by forever, will have flaws, and they will accept that and move on. Someone who cannot see the flaws is an extremist and cannot not be reasoned with.