Everything you've said was already said about the bomb but they built it and used it anyway.

There will always be those who think they're right. There will be those who think they are doing their god's work and they themselves will be protected or will be given special access to the highest levels of heaven or will receive 72 virgins--whatever.

Suicide bombing? That's stupid. You kill your own personnel and then you have to recruit more and they will be less likely to kill themselves, etc etc. But it happens.

Then you have groups who believe they know how to control the spread of the disease such as choosing vectors that aren't on their side of the world or by using diseases that are less contagious, etc.

Then there are groups who could do damage on a limited basis but threaten us with more if certain demands are not met.

As far as giving people Alzheimers, they don't need to invade us. Just watch us run our country into the ground or watch it careen out of control forcing the rest of the world to take some kind of united action against us. They may have to anyway just to try and keep the contagion from spreading.

And yes you can do this on your own with ordinary materials--that's what I've been saying since I started this thread.

Sooner or later, somebody is going to do it and all your insisting how stupid and insane it is will mean nothing to them.