They're a bunch of idiots, and completely going about it the wrong way. They've targeted a shop that is trying to do the right thing, which they should be supporting, not vilifying.
What would be more productive is to stand there giving away free booklets with delicious sounding vegan recipes in them. I'd be more likely to try a recipe for a vegan meal presented to me like that, than I would be to not buy meat because some unemployed nitwit is standing between me and the meat counter.
Their actions are never going to convince someone to stop eating meat or animal products, in fact, it's more likely going to encourage people because they are pissed off. If they went about things the right way, and encouraged people to reduce their use of animal products, rather than cut it out altogether, and to buy ethical products over mass produced, would be a far more effective way of working towards their goals.