The problem with helping the customers in the same manner is, how do you prove that a serial number matches that customer's TV?
Serial numbers are not logged at the point of sale (at least not in the UK), and customers are not likely going to check their serial number unless they're asked to (such as calling Samsung for support). If the TV is wall-mounted, chances are it's going to be difficult for them to even reach the serial number.
What if a customer sells their tv to someone else - could they then report the serial number and get it locked? (and for added effect, remove the label and/or swap it with a fake one)
We already have scam phone calls where people ask for sensitive information - what if they ask for tv serial numbers then threaten to block them if they don't pay up?
Implementing such a system leads to a whole host of problems.
Even if a customer has their serial number, Samsung has no way of knowing that serial actually belongs to them. Even if the TV is registered with Samsung after the purchase, with that serial number, who thinks to contact Samsung and de-register it again?
Apple have their "Find my..." system that locks their Macs, iPhones, iPads, and iWatches - no repairs can be carried out and the device can be remotely locked by whoever has it registered to their cloud account - does Samsung really want to go down that route for TVs - an item that's not typically known to be portable?
How often are TVs stolen? Is it that serious of a problem to warrant the manufacturer's implementation of a system to lock them down? Is that going to be a selling point? "If you buy a Samsung, when it invariably gets stolen, we can remotely brick it... it won't help you get the tv back, but you'll be happy knowing that the crims will be upset with you and come back for revenge... Hope you improved your security?"
What courtesy is it to customers when they don't benefit, whether the tv is remotely locked or not. Apple locks deter thieves from stealing apple products when people are walking around on the streets with them. A Samsung remote brick isn't going to deter a burglar from breaking into your house - if they're of a mind to pinch a tv and have the means to do it, they're not likely going to be put off by the outside chance the owner can have it remotely bricked if they connect it to the internet.