SHPAML is not a pseudo-programming syntax. It is purely a markup language, so there are no programming constructs.
SHPAML very deliberately tries to be a lightweight abstraction on top of HTML, unlike wikis and Markdown, which operate at a higher level abstraction. I am a huge fan of wikis, so I value the higher level abstraction at times, but I also see the need for an in-between solution.
I have not used Markdown much, but I see its merits as well.
I'm not being critical of your tool in particular so much as wary of the flock of thin syntax transformers that have come out lately. They're fun projects, but adding yet another mutually incompatible data format is probably only a net gain under relatively specific circumstances (small teams, for starters). I like Markdown in this regard because it's downwardly compatible with how people would write anyway. You're right that it's at a different level of abstraction, though.
And about the name - I'm really tired of hearing the same Monty Python jokes all the time, but that's my problem.