There is a fundamental dichotomy here - or perhaps it's a trichotomy? Or is there a 4 headed version of same?
In most cases, in common law jurisdictions like the USA and Canada, there is nothing legal stopping you from taking photographs in a public place.
There are some - very few - legal restrictions about what you can do with those photographs. Those legal restrictions relate to public rights, enforceable by public interests - aka the government.
In addition there are also distinct private rights attached to some of the subjects that might be found in those photographs. Things like images of individuals, signs, art work or commercial items that form part of the image depicted in those photographs.
Some of those private rights were originally recognized as part of historic common law. Others were/are purely creations of statute law.
All of those private interests aren't enforced by the government - it's up to you, and your dime, if you want to do so. In some cases that means the incredibly expensive, time consuming and complex civil courts. In other cases, governments have created other specialized mechanisms for enforcement, but it still will be up to you, and your dime, to make use of them. And in virtually every case, recognition and enforcement of those rights has been modified through statutory provisions.
In each case though, it isn't illegal to breach a private right - there is merely an available personal remedy for the breach.
Just as there is no legal right to free speech in the USA - just a prohibition stopping the government from legislating against free speech.
It's Canadian Thanksgiving Monday here today. There is nothing in the law here that prevents the hosts at Thanksgiving dinner from shutting down talk about politics, religion, or for that matter the joys of Hasselblads or camera repairs at the Thanksgiving dinner table - none of the family have any rights to say anything about those or any other topics, if the hosts say no. And it will be exactly the same situation and rules when American Thanksgiving comes around, both on this side, and on the other side of that Canada-USA border which is just 13 blocks south of where I'm sitting. As long as no laws are passed, you folks to the south of here have no grounds to complain of illegality if your hosts tell you and your quarrelsome relatives to stop arguing about something.
In other jurisdictions - particularly in civil law jurisdictions where Napoleonic Codes or other similar provisions are employed, the legal rules take different forms. As a result, there are legal rights, responsibilities and remedies - both public and private - that take different form. Where you are is critical to the question.
But all of that is different from what was asked by the OP - they didn't ask about legalities, or personal or public rights - they asked about ethics and values and how to deal with people's interests and feelings. Some of that is complicated by overlaps with legal rights, responsibilities and remedies. Or even worse, complicated by misunderstandings about legal rights, responsibilities and remedies. In any event, the answer is highly dependent on expectations of the people in the groups involved - a sort of cultural expectation reality.
There are members here on Photrio who have experience navigating the waters of associating photographically with protests and the people who participate in them. That includes experience with the people who respond to or have to react to such protests. Ding so effectively involves techniques, knowledge and, most importantly skill interacting with people in challenging circumstances.
In my case, any experience I've had in dealing with such things is both relatively small, and quite dated, so I'm unlikely to be much help. But there are others here who are much better equipped to assist or to make appropriate referrals.