Gosh, how long do you have, lol?
Don't look at the symptoms in isolation (terror attacks) but try to trace how we've entered a situation where these things are occuring, and what political and social reasons are in play that allow such events to happen.
Gurbani speaks against Yoga in the sense that its the way to God. Yogis were an odd bunch, some walked around naked, some were living in mountains. Yoga like that, that's totally anti-gurmat for Sikhs. If there are Sikhs doing it for exercise then its fine, its a nice way to relax, release stress and stay healthy. That's fine as well, however actively encouraging it as a tool to get close to God is something completely different.
Tantric Yoga has aspects of eroticism within it. I can't speak to if its done in other places but its got a huge following in certain parts of India. Though this whole topic is alot more deeper than people let on.