Phil Torres is held in particularly low esteem by people on the EA Forum for what I think are good reasons: his arguments are often flimsy and on top of that he has made various unfounded accusations. But criticism of EA in general is one of the more popular tags and has some really good material from people internal and external to the EA community who have careful arguments-- here are some I recommend:

• https://forum.effectivealtruism.org/posts/uxFvTnzSgw8uakNBp/effective-altruism-is-an-ideology-not-just-a-question
• https://forum.effectivealtruism.org/posts/Jxfq6xCP9ZoTBFewA/why-i-am-probably-not-a-longtermist
• https://forum.effectivealtruism.org/posts/LJwGdex4nn76iA8xy/some-blindspots-in-rationality-and-effective-altruism
• https://forum.effectivealtruism.org/posts/pxALB46SEkwNbfiNS/the-motivated-reasoning-critique-of-effective-altruism

That said, these still come from a perspective of doing the most good so if you don't e.g. believe that saving 1000 lives is better than saving 1 life, you'll probably bounce off of the community as a whole.

Also, longtermism is not really a founding principle, it's more of a view that some EAs hold which heavily influences their altruistic decisions. If there are axioms of EA they're something like this:

1)  Consequences matter (which any moral philosophy worth its salt agrees, although to varying extent on what else matters)
2) Pay attention to scope, i.e. 100X lives saved is way, way better than saving one life. 

Yes, it's open to debate on the merits of its founding principles. I'm willing to have a debate, discussion, conversation, whatever, here, in private over a video call or email, or whatever you might prefer.