These are terrorists which most often are not supported by the local populace. So bulldozing the houses of innocent people who had nothing to do with attacks and probably work in Israel is a lose-lose and won’t improve anything. The tunnels are not made by volunteers or hires, they are made by captives which sometimes include entire families. When the tunnel is completed the diggers are usually executed.
Rather than becoming a pariah it would be better to use good intel, listening devices and ground-penetrating radar to discover the tunnels before they’re used.