I am not exactly sure what the fear here is. What will the “unshackled” version allow governments to do that they couldn’t do without AI or with the “shackled” version?

The constitution gives a number of examples. Here's one bullet from a list of seven:

"Provide serious uplift to those seeking to create biological, chemical, nuclear, or radiological weapons with the potential for mass casualties."

Whether it is or will be capable of this is a good question, but I don't think model trainers are out of place in having some concern about such things.