In my dealings with Grizzly customer service, they have been very good at making things right. Go into the conversation with evidence to support your claim and discuss a reasonable solution in a calm way. They have never asked me to return any defective or wrong merchandise.
With selling merchandise in this country there is a common law warranty of implied fitness which dictates that an item is fit for its implied or intended use. The Grizzly catalog state, for the G0602, "maximum tool size: 1/2". It also states, for the G0752, "The model G0752 is a variable speed version of the the G0602". The G0752 shares a common manual with the G0602 and the manual states" The four-way tool post is mounted on top of the compound rest and allows a maximum of four 1⁄2" tools to be loaded simultaneously."
I would not have a problem correcting the fault myself and have done so many times in the past. However, expecting a vendor to do what they are legally obligated to do is not unreasonable. Additionally, forcing their action on this may very well eliminate the issue for future buyers.