Lasers do like 1% damage, so they aren't great for racking up damage. If you're laser camping someone, it's because you want them to approach you. You're saying "I'm going to stay over here for 8 minutes if I have to. If you don't try to stop me, I'll just win by having less damage." They have to go over to you and stop you. Laser camping's not about damage, it's about forcing your opponent to approach.
According to Ping Pong the Animation, human reaction time caps at .1 seconds. Idk the validity of that, but it's pretty slow compared to the 1/15 second it takes Fox to jump. As such, people put stuff into muscle memory. If they want to wavedash, they just put in the inputs without thinking about them. However, most people take this further and have a bunch of stuff planned out ahead of them in terms of tech skill. If they want to reverse SHL, they'll have the dash, sh, turnaround, laser, and fast fall all in their fingers. Same with waveshining. If you shoot someone as they're doing some kind of tech like that, they may end up doing a side-b. The idea is to make their memorized inputs do something they didn't intend.
Falco's laser doesn't do knockback afaik. It does flinch, meaning that the hitstun is over in a couple frames but your motion in all directions is completely halted. It takes longer to fire a laser than it does to get out of it, and from what I read, getting up after a missed tech is different in melee than in brawl. In melee, when you're getting up, you have invincibility frames for a period during your getup animation, and if you get hit while you are vulnerable but still in your getup animation, you are knocked back like normal.
As for the jab lock against a wall, I think you can smash DI behind Falco in his rapid jab combo and get out. Hit shine sends people up, so they'd have to walltech every single shine in order for you to have an infinite. They'd likely just not tech and get out.
Besides that, Falco's combo game is so good he effectively has 0-deaths on everyone with the right reads and tech skill.
You mentioned that you like to shoot lasers whenever you have to opportunity. This is dangerous because it gives the other player a rhythm to use against you. If they know ahead of time when you're going to shl, they can waveland across a platform, letting the laser go under them, dash off the platform, waveland, and punish. If they know the height you're going to laser at they can crouch or dash under it or jump over it. Fox is great at full jumping over lasers and falling with an aerial. Sheik and Marth are really short when they dash, so they like to dash under the lasers.
tl;dr: Predictable lasers are very punishable.