When you cook something on your stove, it becomes "processed food". If you have an aversion towards anything you hear is 'processed food', you are basically a chump.
The problem is industrial food is usually made with industrial grade additives: Monosodium glutamate, modified palm oil, various stabilisers, buckets of sugar, etc - I would list more, but I literally threw away the worst offender I had on hand (Pre-made meal-in-a-jar)
I'm glad you bring up MSG because it's a great example of something that's been repeatedly proven harmless but people still irrationally fear. It also occurs naturally in large amounts in many foods.
People are stupid when it comes to food. It's probably an evolutionary thing, from back when heeding food lore from other people could mean the difference between life and death.
I have severe acidic reflux - I can pretty quickly tell when something is laden with MSG - I literally start gushing acid within few hours.
Also the issue is of amount - some processed foods just go nuts
It occurs naturally in many foods (at varying concentrations), but that doesn't mean we have to smother everything else in it. It makes snacks harder to resist, which is why industry likes it. That doesn't mean I have to like it. Its current usage basically encourages unhealthy eating habits.
It doesn't make snacks any harder to resist than salt.
From a food production standpoint, MSG is a popular additive because it offers an affordable way to enhance the flavor of a wide variety of savory foods. MSG can also be used to reduce the amount of sodium in foods - it contains 30 percent less sodium than table salt, but its flavor-boosting ability keeps low-sodium foods palatable.
All MSG does is add umami flavor, which your body responds favorably to as taste is an indicator of nutrition. So in some way, yes, MSG does make the 'snacks harder to resist', in the same way that literally any flavor makes food harder to resist.
Our body wants sweet/salty/umami/bitter flavors depending on current needs, and naturally gravitates towards foods with those flavors, as taste is a direct indicator of nutritional value.
My point is that salt also produces that effect. And sugar. And bitterness, for that matter. Literally every flavor is a biological indicator of nutrition.