The problem is in the original question. You start with a false premise, so anything you say to defend can easily be attacked.
Texas is not granting a new right under law. They are removing restrictions upon an existing right. The question should be, "What harm will removing the restriction on OC of handguns cause."
Opponents have thought much on how to phrase the argument, to put every advantage to their side.
you are correct hovercat, the OP's statement is a false premise, and the additional information added by the poster 14 posts into the thread just serves to add further confusion.
however, i must disagree with your statement, as i have taken the liberty to bold...the Texas legislature is not removing restrictions but rather imposing further restrictions on the OC'g of the state's citizens to OC a firearm by 'making' the citizen get a privilege card if they wish to OC a handgun.