There are some things that are commonly seen in the early stages of many poly relationships. Often, they are rules or policies that are set in place in an attempt to reduce/manage insecurities, jealousy, or to maintain the "primary" couple bond as the most important. Things like One Penis or Vagina Policies, no sleeping over/travel rules, restrictions on access to other partners, limits on the number of additional partners that one is "allowed" to have, unicorn hunting, or attempts to mandate dating the same person/people. Let's call this general class of ideas "Training Wheels" for the poly person.
Training Wheels serve a valuable function for many of us. They give us a way to prevent deeper injury while we are learning new skills. They give us confidence that we can do something, even when it's a little wobbly around the edges. It's a way to feel in control of something that isn't vaguely under control, because we aren't ready to relinquish that control yet. There does come a point where the skills are there, the confidence is real, and we're ready to fly without a safety net. Keeping those policies in place at that point just slows us up, holds us down, and prevents further growth.
While there are some lucky folks out there that seem to have been hatched from poly eggs, coming straight out of the box fully plugged into the idea that personal freedom and choice in the context of relationships is self-evident, most of us have to do a bit more work to get there. The thing is, once you've gotten to the other side of the fence on something that you may have once considered a "hard limit" for you in relationships, it seems pretty obvious that it may not be the best way to do things, and when you see others who are still in that space, of course you want to bring them along to the place where they are sharing the same perspective on that issue. This is where we often hear complaints about the "Poly Police".
There isn't a "right" way to do poly, but there are ways that work better than others. If you've worked hard to find those ways, it makes sense that you'd like to share that wisdom with others, to help them avoid some of the myriad of "doesn't work so well" ideas that have been discovered.
Here's what I've noticed though: some of us just don't learn things by reading about them, we learn by stepping in it, repeatedly. Even if we are proactive enough to read through the many fantastic resources available online, in books; even if we have conversations with others who have been there, done that, got the t-shirt, sometimes, the only way to really truly understand something soul-deep, is to do it, do it badly, be hurt, hurt someone else you care for, and experience it.
So, those of you that feel peeved or offended by the Poly Police trying to "tell you how to do your relationships", understand that it is often motivated by concern, empathy, and a desire to help others avoid living some of the most painful moments they've experienced, decisions that have damaged or destroyed cherished relationships, and rules that have the opposite effect of the intended result. Think carefully about the concepts that are behind the advice, even if you aren't ready to take it yet.
Finding the right time to take off the training wheels is a personal choice, but it is one that needs to stay on the radar. Each new relationship has it's own growth curve, so it's possible that you may find it important to have certain training wheels on in one relationship, while another is perfectly fine without them. Re-evaluate often, and push against the things that you feel as limitations in your relationships in a way that is compassionate for all involved. Just like when you were learning to ride a bike as a kid, chances are pretty good you'll fall down, but the solution is still to get back on and keep trying until you get it.