Legal seems a very low bar to me. I expect organisations/companies to act ethically. They rely on the communty in which they exist, they rely on tax payers and consumers, they do not exist, nor thrive, in a vacuum. They owe us all to act with that in mind. In a free society it has to be possible to protest, if they exploit their power/position.
Changing laws is very slow work, and so it should be, of course, to ensure the lawfulness of the process. If an entity poses a threat to the environment, or to individuals, or to important common values, that slow process can be fatal. Protesting can be much faster; most organisations/companies care about public opinion. And even if it's not about very important issues, perhaps it's just about something like uglifying a building, for instance - what then? Of course protesting such things is legitimate, and often even desirable.
It can only be effective if
1) it's actually true and can be verified as such, in which case it should be dealt with legally even if you also want to raise awareness of it in the interim
2) enough other people share the same sentiment
3) the company in question cares about whatever is being protested about in the first place
Often, none of those are true.
Consider the whole "Occupy Wall Street" thing from 2011. Hypothetically it was supposed to be a mass statement about wealth inequality and the role of money in politics, etc. Which are fine things to raise awareness of, and to
campaign the government for redress thereof. In reality, however, this group of people accomplished nothing at all other than to make themselves a nuisance and inconvenience everyone around them. They didn't effect any change at all. Not a single company changed their business model as a result.
Boycotts, on the other hand, have sometimes been successful. You know why? Because they're not protesting a company, they're appealing to consumers to withhold their money from the company in question - consumers who have been convinced that the company's behavior is bad enough that they shouldn't give them their cash.
Worker strikes are more similar to boycotts than to protests, although they can backfire spectacularly. If the public largely agrees with the workers, strikes can be effective. Sometimes strikes accomplish what the workers want not because the public agrees with their complaint, but because the workers hold the public hostage. Teacher strikes, for example, sometimes end up resulting in better concessions for teachers... but they also tend to piss off parents who are suddenly left without the ability to work because their kids can't go to school.
At the end of the day, companies only care about public opinion if that opinion hurts their bottom line. Protests generally don't cause financial pressure.
