"Never try to teach a pig to sing. It wastes your time and annoys the pig" (Robert Heinlein, Time Enough for Love)
When trying to become agile, Team members quickly tend to fall into three main categories (the percentages are purely based on my empirical observations and should not be seen as set in stone or based on scientific study!).
10-20% will "get it". These are the guys and girls who will be able to use the techniques to learn from their mistakes, spread their wings and perform. They are the future of the new, agile Company.
60-80% don't "get it", but are willing to try, or at least toe the line. They need more guidance about how to work efficiently, and that things are OK. They need more reassurance that the Team does not need this, that and the other supporting items (eg the massive Big Up Front Design documents, or a full specification signed in triplicate). With careful nurturing some people in this bracket will "get agile" (and trust me, the lightbulb moment when they do is one of the most satisfying moments of any Coach's career...). However those that don't really understand the principles do follow the basic ground rules and are not actively damaging to the agile process or the Team as a whole. In fact gentle pushback and respectful challenge from people who don't fully understand is healthy and productive.
10-20% of the Team don't "get it", will never "get it", and in fact really, truly don't want to "get it". These people are the biggest danger to any agile transition since they are not always obvious but will actively undermine changes to the status quo. More obvious behaviours that I have witnessed have included aggressive, disrespectful and/or unecessary challenge, refusal to adopt new working practices agreed by their Team (including themselves!), continuing to use old heavyweight processes in addition to the lightweight replacements, refusal to engage with the Team as an equal member and so on.
Anyone falling into this final group can cause huge amounts of damage to any agile Team but this damage is multiplied in a fledgling agile environment since the result will be bad decision making in order to placate someone who has no interest in working smarter.
So what to do? A difficult decision needs to be made but ultimately the damaging disruption has to be neutralised as quickly as possible - usually the easiest remedy is to transfer them from the agile Team to one more suited to their skills and temperament.
Alternatively you can keep trying to educate...how are you at giving singing lessons?