For example have anyone noticed that we don't get to choose between silverlight, flash and html5 on many microsoft sites ? we are forced to install craplight..erm..i mean silverlight to watch videos.
Apple forces you to use quicktime. Adobe forces you to use flash on their site. Youtube, hulu, vimeo, etc force you to use flash.
(ms also uses flash on their sites btw)
You're also not "forced" to do anything. If you find your only choice is through one platform, it's because the other platforms "forced" your hand, not because the one platform that you inevitably chose "forced" you to choose it. Now, if you were "forced" from above to adopt a certain platform, then it is that higher agent that "forced" you into using that platform.
Choices don't "force" you to choose them, external sources do.