There’s a variety of reasons a juror can be rejected, with one of them being “the juror is not willing to follow the law, as written”. This seems to be what’s happening here, the law says that if a person does X, the penalty is fine Y, and these jurors are saying “I would not issue fine Y even if you prove they did X.”
To an extent, this is the system working they way it’s supposed to, one of the checks on unreasonable laws is being unable to find people willing to enforce them in good conscience.