Assuming LAFC does the expansion draft the same way Atlanta and Minnesota did, they left Chanot exposed because LAFC has no interest in taking on a high-contract international player in the expansion draft -- they're going to use it for organizational depth and trade bait. They probably exposed him because he has a much smaller chance of being picked than a guy like Sweat, who has a small salary and doesn't take an international spot.
Surely, Chanot could get picked, but odds are LAFC is going to pick guys they can use for trades/organizational depth. Take a look at last season's exposed list, then look at who was actually selected. No one of any import was actually selected.