Hi Samwarren,
You may have a situation where the new principal feels overloaded in her new job or may have a past negative experience with a parent group. So, there's a good chance this isn't a case of not being wanted but more a case of the administration not fully appreciating the value of a parent group at this particular time. Consider having a few parents who are motivated and invested in establishing a PTO (you may want to take a pass on this b/c the principal is your boss) meet with the principal to share their thoughts on why an independent PTO is a huge benefit to the school. Listen to the principal's concerns and see if there is a way to meet each other half way.
Let the principal know that an independent parent group can be very successful at fundraising because parents feel personally invested and they want to help. As importantly, an independent group fosters a sense of community that is driven by parents and not strictly driven by the school.
Here are a few articles about working with the principal that may be useful.
How To Work With a New Principal : https:/classic.ptotoday.com//pto-today-articles/article/676-how-to-work-with-a-new-principal
Negotiating With The Principal : https:/classic.ptotoday.com//pto-today-articles/article/176-negotiating-with-the-principal
Make the Principal Your Partner: https:/classic.ptotoday.com//pto-today-articles/article/209-make-the-principal-your-partner