Even just having investments in Cannabis stocks can cause a lifetime ban https://www.ctvnews.ca/canada/why-investing-in-pot-could-pos...

>Even though Znaimer didn’t admit to personally using pot, he was given a lifetime ban anyway because of his investments in U.S. marijuana companies, he said.

>In one case, Saunders said an Edmonton man received a lifetime ban from entering the U.S. simply because he was a part-owner in a Colorado building that leases space to a pot dispensary.

So what is stopping them from denying entry due to search history?

The rationale in the US law is that the crime is an equal moral failing to murder. That may be irrational to you and I, but that is the law.

Just as being an accessory to murder would be considered "very bad" so too would supporting cannabis use in any way. According to US law he is investing in a criminal enterprise, similar to funding a cartel in Mexico. The law doesn't match the common person's perception of severity, but the US border guards will enforce the law as written.

Again, none of this prevents you from merely learning about cannabis. It requires action of some sort to further the use of it.

By that logic, if you owned property that was rented by a murderer, you should be banned as an accessory to murder. It's absurd.

Its more like leasing a room knowing it was Dexters kill room. That said I'll go no further justifying US pot laws. But the failure is in the severity assigned to the "crime", everything that follows is rational if you accept the premise that it truly is akin to murder.