Obviously, in an ideal world, the clear answer would be yes. However, is it appropriate to actively ignore the social aspect of conservation and focus exclusively on the environmental side of conservation if it means that a piece of legislation has a greater probability of being passed and implemented, rather than designing idealistic policies that are unlikely to ever be passed?
To what degree should conservation policy be compromised, and which stakeholders should be included and which ones should not be included?
You're sort of hinting at the evaluative idea of "nature for nature" versus "nature for people."
The level of stakeholder and citizen inclusion in conservation policy is really dependent on what is being conserved. But it should be general practice to include all those who will be impacted by the policy. For example, if the goal is to ascertain a parcel of land as a nature preserve, then those in the surrounding areas, residents, local businesses, indigenous communities, scientists, etc. should all be included in every step of the process.
If the policy is more abstract and is meant to influence behavioral change, such as the banning of plastic bags, while stakeholder and citizen inclusions is still important (because democracy), it would be more impactful to simply pass such a bill quickly. In this particular instance, we know that plastics are undoubtedly a bad thing, so letting everyone voice their opinion for the sake of fairness might be counterproductive.
TL;DR - It's very case-dependent. It is also very cultural-dependent. If a certain demographic values nature more than people, policies that prioritize nature will win out. If a culture values people more than nature or see people as separate from nature, then the interests of people will always win.