I can understand your sentiment where you may not trust these benchmarks to be unbiased. However, I am fairly certain if they are, it'd be pretty easy to prove. Do you have any sites that show to the contrary?
Furthermore, one of the major points of all the "new web languages" is to add (optional) typing, which is where the biggest speedups come from modern JS engines -- type inference and unboxing. So to strip them of these features is akin to saying "you're allowed to benchmark C against Python if you made sure everything in C is type checked before being operated on, even if you know their types." So I'm not exactly sure what you're objecting to here.
Which one of them have expressed interest in each of the language the other is proposing? Let me give you a list:
Think about it: the point that everyone is rejecting everyone else's language is because they all have their own wares to peddle. Of course "they" all express negative interest in supporting each other
At the end of the day, of all the modern browsers, which one has the highest market penetration/momentum? If you're going to target the "next generation" of web languages, which one would you chose?
You knew the job was dangerous when you took it, Fred. -- Superchicken