First, that is cherry-picking. We can find lots of examples of protest being effective. [0] And as I pointed out elsewhere, the right wing - while teaching their enemies to quit - embraces activism fully and has been incredibly successful.
It's only ineffective if your measure is immediate, complete victory. You don't win everything, you face defeat, and you quit? Then I agree, your protest is useless. You think you are somehow entitled to results? Yes, your protest is worthless, a pantomime. Protest isn't a ritual you perform - a raindance that you do - and then the gods respond with whatever it is you asked for. Protest compels results - it's embracing that you are the agent, you are the power, you make it happen; the enemy will give you nothing. If you don't understand that, if you aren't planning for it, if you have no strategy that will compel victory, then you're just entitled. (I think the latter is the problem with most of the protests now - they're doing raindances.)
And you go around telling people how hopeless it is? Have you ever accomplished anything? Has anyone who has ever said those things? People saying those things are the first problem - if they were on my team, I'd tell them to never say that again or simply don't come back.
Regardless, the protests have altered behavior, including by European leaders and by the most powerful person in the world (POTUS) and a candidate for that office (Harris). They may cost Harris the election by denying her enough votes in Michigan. And though nobody can say for sure, they arguably have altered the Israeli government's behavior, though the protestors will certainly and understandably say, not nearly enough.
Finally, to evaluate protest, compare it to the alternative: silence. Imagine horrors went on and society responded with silence. Imagine how demoralizing that would be to the ordinary person, who does have a moral conscience. Imagine how crushing to public morality if nobody said anything. Protestors are essential.
[0] There was some research, I think from 10-20 years ago, that showed that it succeeds at a high rate. But I don't recall what kind of protest, etc., so I hope someone else knows about it.