corn syrup

The only reason they do this is because in the US, corn subsidies make it cheaper. HFCS is essentially exactly the same as sugar to the body. It's not any more or less unhealthy.

GMO

Another overblown fear. Humans have been modifying organisms for millennia. GMO is not inherently harmful. The main harm comes when companies try and make it so farmers have to purchase seed from them for every crap. That's not harmful to eat. That's harmful for our food supply.

extreme weed killers and pesticides

These all easily wash off, and you need to be washing your fruit and veg because they are dirty.

It's trivial to research this for yourself. Stop listening to idiots on youtube trying to sell you supplements and lying to you about these things.

There are problems and concerns, but these are not them.