Joseph: I’m confused. How am I saying Rava is wrong? Rava presumably had the authority to say R’ Tarfon erred. I don’t have the authority to say anyone erred (or, at least, any Tanna or Amora; I say you’re wrong all the time 😛 ).
mdd: R’ Tarfon was wrong for two reasons, presumably. #1 is that he did not have the correct Halachah; if he did then the discussion cannot happen. #2 is that, on top of that, his special Chumra is not worth saying because the Hefsed far outweighs the gain.
R’ Akiva is another story entirely. I point out that there are lots of statements from the Tannaim that seem mean to R’ Akiva. I’ve never had a great Pshat why, though I have some theories. In this particular instance, though, I would repeat the same two-step process. R’ Yesheivav (I think) is saying R’ Akiva got the Limmud wrong to begin with. That being a given, we then say that R’ Akiva’s Shittah should be strongly decried because the outcome is so bad that it shouldn’t even be said. Meaning, usually you can just argue with a wrong Shittah and we trust that the right Shittah wins. Here, we have to strongly reject the wrong Shittos so that no one will ever think it’s correct because the outcome of those wrong Shittos are so horrible.