Being able to "theoretically" take out a team doesnt come close to matching someone who has actually taken out the team. Brainwave has bested the JSA with more big guns than the line up in the show on his own several times.
He took down a line up with Fate, WW, J Thunder, Hawkman, Dr Mid-nite, Atom, Sandman, and starman in one story. Then the All Star Squadron came to save them and he took them down too.
He took on and got the best of Spectre, Fate, Starman, Hawkman, Atom, Mid-nite erc in another and did it from somewhere else in the country with just his mental projections
He took down Fate, Alan Scot, Powergirl, Flash, SSK (with the star rod) from orbit with his mental projections.
The post I replied to said theat Icicle, Grundy and Magician (I asume they meant Wizard) were the bbig guns of the ISA, but of those only Wizard is a big gun of this line up.
Comic Shade is easily on the same level as either comic Fate or Thunderbolt (and used by Johnny Tbolt was often useless because he always forgot his magic words).
Brainwave is also close to their level and on the level of Alan Scot in the comics. The Fiddler can stop the while team dead with his ppwer to control others with his fiddle or make walls and blasts of sound.
Comparitively Grundy and Icicle are fodder to those members of the team. Those fodder however are more than enough to take on the likes of Starman and Hourman and then there is all the other members. Dragon King was responsible in the comics for the magic forld around axis held territories that made superhoeres the pawns of Hitler or Tojo if they entered acis held territory, that is without his science and JUST his occultist knowledge.
Johnny sorrow doesnt offer the team that faced the JSA in that first episode anything that would make them more of a threat than the members who were/are in the TV ISA.
All of which is excluding that this TV JSA isnt the one from the comics. Sylvester Pemberton wasnt Starman, courtney doesnt have a Cosmic Converter Belt, Wildcat didnt have a suit that gave him powers and DIDN'T HAVE POWERS. Dr Midnite's goggles don't have a tech readout. We have no guarrantee than any of the fallen JSA are even like their comic counterparts, but as long as the ISA have similar changes to the JSA then the battle was never one sided and there is no reason why the team that took part couldn't win