They could have worded the questions to be more neutral, but so long as they compensate for the rhetoric used by adjusting the scores for the question or balancing it out with rhetoric from other standpoints in other questions, it's entirely possible for some of the questions to be worded favoring one side without making it inherently biased.
As an example, it poses "the freer the market, the freer the people", which is completely a right-libertarian rhetorical statement, but if you already lean in that direction it seems like a normal comment. Likewise, a person who is liberal authoritarian and sees "it's lamentable... blah blah blah drinking water blah blah" statement will find the phrasing normal. However, pose the statements to the other side and both will pretty reliably call the other statement biased.
You don't readily pick out the biased questions favoring your viewpoint because it just seems so natural to you.