You can just label it as "might contain traces of X due to cross contamination". At least that's how they do it in Europe.
But it's not "contamination" if it's an ingredient, so if one thing in your factory has sesame in it, you're better off adding a tiny bit of sesame to everything else than you would be scouring the whole line between products.
Presumably the business folks have run the numbers, and you stand to lose less by losing the sesame-sensitive market than you would stand to gain by making everything verifiably sesame-free. For that matter, your sesame-sensitive folks probably are avoiding the product anyway if it "may contain traces," right?
[0] https://www.food-safety.com/articles/8903-fda-updates-guidan....
This is why lots of disability measures are (or campaigned to be) enforced by government. But now we're out of realm of free market and on to production quota, and that comes with its own consequences.
My point is it's not profitable for a large company like Bimbo to target that small segment. A smaller company, not trying to compete with Bimbo, can target that segment knowing Bimbo and other large companies are going to stay out of it. I don't understand why you don't see that as a solution. That kind of thing exists all over. Half the products at Whole Foods or maybe Erewhon are from small indie companies catering to small markets of people that want those things. It's arguably no different than a market that carries foods that aren't found at big chains like a market that has product from India or Russia or China.
If the market is too small then either those that need that need their special foods either have to pay $$$$ until there is a market or make them themselves. That seems normal to me. It's not other people's responsibility to provide for your needs.
There is no market for it. You need customers willing to pay the price. A small company, not trying to compete with Bimbo, cannot afford to sell >$100 USD allergen free bread, because no one would buy it.
You're right, it's not other people's responsibility to provide for your needs.
The problem is, the downstream effects of this policy make everything worse for people with sesame allergies, which is the opposite of the intended effect.