Take the L dude.
Not only is that clearly not the reason in this case, of what you say is true (and I believe it considering your behavior) that's a pretty damning indictment about your collective personalities.
Youre blaming OTHERS for leaving your cause because YOU'RE impossible to put up with. Pathetic. The literal definition of that meme where the dude puts the stick into his bike spokes and then cries about it.
If you hate non-vegans so much then stop talking to them. Simple as.
On the basic end: because they're cheaper, use less energy, are more reliable, and last longer.
On the fancy end: have you seen demonstrations of Audi's matrix LEDs? They have the ability to dim specific areas dynamically, so that they can track incoming traffic and keep them in a dim-zone while still keeping the road and shoulders well lit.
Keep in mind that there is nothing special about LEDs that make them brighter; they can make LEDs dimmer and they can make halogens brighter, but the manufacturer has chosen not to.