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.
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