By that line of reasoning you could publish a website with information on hitmen for hire and put their phone number beside each listing. After all it's just a sequence of numbers and the user has to manually call or configure their device to place the phone call.
That's more like a tracker. A closer analogy to magnet links is that I tell you a hashtag that's used by a particular sort of hitman, and you use that to find your own hitmen on the social media site of your choice.
