There may or may not be good reasons why your node was down voted. I'm not even going to try and evaluate it.
in reply to -ve XP, node reputation, voting and learning
In a community like this one, if you never get a node with a negative reputation, then you aren't taking enough chances. You can't always be universally loved and appreciated. Don't try and you'll be happier and more productive. Clearly, your progress is positive, feed on that and ignore the downvotes. For all you know, they could be random and you don't want to skew how you post based on that, do you?