It wasn't all that long ago that browsing the internet with Linux was seriously crippled
Many sites in the early days used Active-X, Microsoft's "answer" to Java, which was only readable by IE and IE for Mac.
I remember not being able to use government services and banking sites because of this.
Because of the huge installed base of MS products, many govs and businesses just rolled out MS-centric solutions without any care for Unix, Linux or Mac.
Trust me, you don't want the web to go back to that.
It may not be MS at the helm this time, but it's easy to see that if there is a content-restrictive standard instituted for the web, there will be great pressure for it to be applied (even in places where it may not be needed!) and the collateral damage is inestimable.