This is where I got my information from: https://www.theguardian.com/news/datablog/2011/jan/28/muslim-population-country-projection-2030
That '8% by 2030' figure is for the whole of the European continent and therefore highly misleading. European Muslims are highly concentrated in Western European countries-for instance in France the Muslim population was already around 8% in 2011. The Pew Forum data was also compiled before Merkel's 2015 'Open Door' policy. I think it's very fair to say the Muslim population of many European countries will approach 20% or more within our lifetimes supposing current trends continue.
Keep in mind 17% of the current US population is Hispanic and look how much political power they wield as a group in an electoral system that operates FPTP.
I still don't get the whole "25% of the population in some places" bit. By some places I assume you mean relevant countries in Europe, where it simply isn't true. Large Western countries we're talking about 7-10% by 2030, with the UK at 8.2%, Sweden at 9.9%, Netherlands at 7.8%, France at 10.3% and Germany at 7.1%.
I can't actually open the original Pew data and there's no actual indication of when that's from. It could have gone up with migrants or could have stayed at similar levels with decreasing birth rates, but again with no indication of when it's from it's very difficult to know.
As for if minorities get power, then surely they deserve it; that's how the system is set up.
If it's FPTP then even if all Muslims voted for a single party (ShariaLaw4All) then they'd have 0 power in the UK as they'd still have a minority of the vote. FPTP makes it incredibly difficult for parties outside the main 2-4 to have any meaningful impact on governing.
If they're in a proper political system like the Netherlands then they'd be like any other populist party and would draw a portion of the vote and either be ignored when coalitions are formed or have a minor impact on policy changes when part of a governing coalition (as should happen). Geert Wilders was part of a governing coalition and did fuck all.
I really don't get the whole panic and fearmongering regarding an increase in Muslim population. Even if/when Muslims DO take up 25% (or 50%) of the population, if it's entirely through childbirth then you'll still have to wait another 18 years for them all to actually be able to vote. Any immigrants won't be able to vote immediately either, and will have to live there for X years and become citizens. If they're able to do that then in many places they'll already have to speak the language and will already be integrating to some degree.
You guys let media headlines influence you way too much.
Edit: Also, please provide some evidence for
in the UK it's the other way round. The younger generations are actually more likely to hold extreme views on most things, though some are more accepting of LGBT people (though when I say 'some' they're still very much a minority viewpoint among their age group).
And the video doesn't play in the UK :/