I had some time on the mower this afternoon to give this some additional thought. I don't think the "loophole" is insurmountable. I think an officer with a reasonable judge could make those cases all night long. The TWRA rule doesn't have anything to do with someone's statutory right to carry a firearm. It just means you can't be in possession of thermal equipment while doing so. That choice is up to the individual.
I think you may have a judge problem. He may own property with hog issues so he is siding with the culls. He may not want to get into the constitutional rights discussion (although I don't think that is in play). Who knows, but with what you have dealt with, it is worth trying to make an appointment to sit down with him.
While I was full time in the field, I basically had three judges in the two counties I worked the most. One was a total joke. He wore "glasses" with windshield wipers on them on the bench. Court with him was always a circus. My main judge was so-so. He was very political, and protected certain folks in the process. You never knew how a case would go with him. He liked to see multiple charges on someone so he could dismiss all but one. The third judge was very fair. If it was a solid case, you got a conviction and at least a minimum on the fine. He didn't want someone loaded up on for him to dismiss cases.
If the judge is not going to dismiss everything on these type cases, go on up the TWRA chain of command and offer some assistance. I see no reason why a decoy hog (or deer) that gave off a heat signature couldn't be made. Get a group of landowners together to cover the costs, and offer up your farm for it to be set up on. Once they shoot from the road, that is an additional charge in addition to the thermal charge. Unless the judge is totally unreasonable, I can't see how it wouldn't stick.