That's fair. It would be cool if there was a way to measure this empirically. I don't really see from my own experience that it has this effect: I'm sure I've alienated some people by seeming extreme, but I can also point to more people than I can easily count who have become vegetarian after talking to me about it, and I think we only got talking because I was strict - because being strict is more noticeable, and perhaps more impressive. And when I explain my reasons, I've never had the response "that seems overly dogmatic". 

But I'm not sure that this is even the main reason not to eat meat. Related to my point (1) above, I also don't want to eat meat (or even want to desire it) for the sake of my own psychology: because I want to view animals similarly to humans, and I think eating dead people is gross. That might seem like less of a rational reason, but I think emotions are important motivators and reinforce our rational beliefs, at least for most humans. 

Given that animal NGOs, according to the data presented in this article, are struggling to engage the media and impact the population, I wonder whether how much weight we should give to the various suggestions they provide? Might it be better to instead ask journalists/influencers who have proven success in getting attention on animal topics how they view this, and what thoughts they have about how to be effective?

Wait up, the USA didn't even make the list...?!

Surprising, although I guess this is just because there are plenty of EAGs in the US already.

I think it's right to at least be open minded about the possibility that their lives might be generally good, all things considered.

To answer your question: insects don't have hearts because they don't have blood. Oxygen is transported to their cells by many tiny tubes (tracheae) extending from holes (spiracles) all over their thorax and abdomen.

I suppose I agree with this. And I've been mulling over why it still seems like the wrong way to think about it to me, and I think it's that I find it rather short-termist. In the short term if farms shut down they might be replaced with nature, with even less happy animals, it's true. But in the long term opposing speciesism is the only way to achieve a world with happy beings. Clearly the kinds of farms @NickLaing is talking about, with lives worth living but still pretty miserable, are not optimal. Figuring out whether they are worth living or not seems only relevant to trying to reduce suffering in the short term, but not so much in the long term, because in the long term this isn't what we want anyway.

"but it seems important for my own decision making and for standing on solid ground while talking with others about animal suffering."

I'm highly skeptical of this - why do you think it is important for your own moral decision making? It seems to me that whether farmed animals lives are worth living or not is irrelevant - either way we should try to improve their conditions, and the best ways of doing that seem to be: a boycott & political pressure (I would argue that the two work well together).

By analogy, no one raises the question of whether the lives of people living in extreme poverty, or working in sweatshops and so on, are worth living, because it's simply irrelevant.