It is just those that have a hobby of legislating behavior of those they do not agree with. But they are too dumb to realize it will always come back to bite them in the butt.
Having talked to many of these people I believe that they honestly believe they are doing what is best for the community.
Most towns regulate all signage, at least here in suburban Chicago . . . much less signs on individual homes. We've got one guy who puts up a for sale sign every year on his property; it must be 5 feet by 10 feet or more; made of wood. Ugliest damned thing you ever saw. He gets away with it, I guess, because he's in an unincorporated area and/or the county doesn't pursue it.
There's absolutely nothing wrong with regulating signage whether it's on private property, public land or businesses.
Are you saying that last paragraph as a blanket statement? Do you include the regulating of content?
Regulating things like porn is generally considered acceptable to regulate as a consistent societal moral. These discussions generally center around regulating political and/or social issue content. I'm stating this because I'm sure some yahoo will come in and say, "So, you can put a picture of a naked woman on a sign and that's ok?", and think they actually made a point.
My city regulates business signs though it is only sporadically enforced. Technically if I wanted to change even the font on one of my business signs I would need to get a sign permit even though it would be the same sign. Supposedly it is a check on making sure people have business licenses, but in reality, it is just another way to make you pay them something for nothing.
That's really my biggest fear here... consistency. They say the ordinance will apply to everybody, including developers, real estate signs, etc., but I fear actual enforcement will happen only against political yard signs, social issue statement signs, and so on. This is a fairly religious area of the country and abortion and Biblical quote signs are fairly common.
The sign I mentioned above in the nearby town is religious in nature, and that's really why some people are bothered by it. My suspicion... and this is only a guess on my part... is that they want to regulate size not because it is a big problem that needs to be addressed, but rather because they can regulate them to be small enough that they cannot be read.
As for political signs, the should be subject to size limitations without a permit or approval of location. I say this because in my area, the GOP/Americans for Prosperity folks have erected some pretty huge signs on private property at locations where they obscured the field of vision for cars coming out side roads/stores onto main roads.
Any sign that disrupts sight lines for drivers and pedestrians and bicyclists should be strictly enforced. That's a common sense safety issue.