Wow, there is some premium A grade Salt going on here. But...... No-one ever straightlined a trail before E-bikes were invented . I get it. The guy with a the motor that puts out no more wattage than you probably can is destroying your trails. And the gatekeepers of mountain biking needs to take up arms and cull the lot of em.
But really, Fuck off. It comes down to the individual. If some prick is intentionally cutting the trail, call the guy out and tell him why it's not acceptable. This goes for motorised and non motorised riders. E bikes aren't the problem. Lack of direction and education is what's wrong here. Talk to your local clubs and see if there is a way of giving new riders trail etiquette sessions or introduce codes of conduct to your trails for everyone.
If you don't like E bikes. Good for you, don't buy one. It doesn't matter. We are all just people out riding bicycles, having fun and that is a good thing. The only difference is one doesn't have to work as hard on the way back up. I love my E bike but I'm not going to stop riding my regular bike because of it.