King Daniel wrote:
But Enterprise showed us is was practical and known to be by Starfleet, hence the discontinuity and this entire discussion.
Enterprise showed sensors that could see easily through 'practical' 22nd century cloaking technology. And this technology failed to defeat the sensors from the future for more than a century.
'Balance of terror' cloaking technology is nothing short of revolutionary in that it does defeat said sensors, after more than a century of failure to do so (it's comparable with the real-life invention of an efficient, commercially viable fusion reactor tomorrow, after 'only' 60 years of failures) - and the behavior of Kirk&co is fully consistent with this interpretation.
What you are trapped by, King Daniel
, is '80-'90 fanfiction - you apparently internalized its interpretation of the relevant lines in 'Balance of terror' (that no one saw/had any form of cloaking tech previously).