This person had a few major spelling errors not found in Lenstra's published papers, so maybe it's Lenstra making bad spelling errors since he is Dutch. His papers would be edited heavily. So you need to find examples of him with no editors.
Here's one of his papers, well done and probably heavily edited.
There's a big difference between writing a forum post and an academic paper.
Looking at the hypothesis from the opposite direction, what comments has Hendrik Lenstra ever made about Bitcoin?
If he was satoshi surely he wouldn't say anything or at least try to distance himself from it?