[gorilla_fight]

Consider if lectins were not a risk when heating food, then castor beans would be completely safe to eat after cooking: the toxic component of castor is ricin, a lectin.

The most cooking can do is reduce or mitigate the harmful effects to some extent. Fermentation is another technique but neither reduces the risk to zero.

"(as any other protein)" is not true either, consider for example peanut allergies, and related allergies such as tree nuts and soy. Cupins, prolamins, profilins are known protein families which can cause allergic reactions. Hence the warning you may see on food labels:

Allergy information: This product was processed in a facility that processes peanuts, tree nuts, soy, wheat, and dairy products.

even if they are cooked.