I've also seen this on FB and was able to read it without difficulty. I actually doubt the claim that only a few people with strong minds are able to read it, however... On FB, that post traveled around a bunch of my friends, and all of them were able to read it fine. I tend to think it more like what the 2nd example states, in that the human mind is really just that powerful, that it tries to make sense out of what seems to be random characters. Also, with the first example with numbers, I noticed that the numbers that they used were very similar to the actual replaced letters, giving the "word" an even more familiar look that our minds can more easily parse.
In fact I've even heard that a universal character replacement scheme for coming up with a password is now being condemned as being too easy for hackers to crack. A universal character replacement is where certain letters are replaced by a different character that has a similar structure to the original letter. More sites are requiring "strong" passwords which is usually defines as having a mixture of letters, numbers, and maybe even other characters. But people still try to come up with a password that they would be able to remember, so people are starting to use this universal character replacement system to come up with a "strong" password according to the requirements yet is still easy for the person to remember. Unfortunately the problem is that certain characters are almost always used as the replacement for some other character (hence why it is defined as a "universal replacement" in that everyone using the same alphabet tend to use the same replacements). For example, '@' is often the replacement for an 'a', '$' for 's', '!' for 'i', '3' for 'E' etc. As a result, it's fairly easy for a hack to just start using these alternate replacement characters in trying to crack a person's password. For example if a person decides to use their cat's name as a password, it would take a hacker too long to come up with G@rf!31d as the character replacement equivalence for Garfield...