You're not wrong but I think this exchange might have gone differently if the tone wasn't so incredulous from the start. Perhaps something like this:
"I know JavaScript is assumed to be universal these days but since this is really just text it would be great if it just displayed the raw text as a fallback for when JavaScript wasn't available."
I know it's kind of silly but how we present something can dramatically change the response. But in fairness sometimes a direct and plain explanation for why something is bullshit is the only way to get things noticed or done too.
"I know JavaScript is assumed to be universal these days but since this is really just text it would be great if it just displayed the raw text as a fallback for when JavaScript wasn't available."
I know it's kind of silly but how we present something can dramatically change the response. But in fairness sometimes a direct and plain explanation for why something is bullshit is the only way to get things noticed or done too.