In this specific hypothetical, sure.

Or it could mean the conveyor next to it uses lots of sesame oil and they can’t guarantee every single particle stayed in that belt.

Or it could mean the conveyor on the other side of the factory is and they don’t want to risk it.

Nobody knows the specific reasoning a company has for adding it in unless they had insider info from the company itself. Everything else is pure speculation.

Have you ever cleaned up sesame seeds? The article's "remove all the sand" analogy is exactly on point - they're tiny and get stuck tight in every available crack. No normal cleaning process is going to remove all of them.

I'm pretty sure the producers involved understand their costs better than you or I and have concluded the optimal outcome is to add an epsilon of sesame cost than a multiple of that of additional decontamination cost.