Well, no, that's not true and it's easy to verify.
It's significantly faster than the iPad 2, about 1.5x, in all but multi-core geekbench (no surprise, given the core count) where it draws level.
Better battery life too.
http://www.macworld.co.uk/review/ipad/new-ipad-2017-review-3656385/
Compare Geekbench to MacWorld's own 6s review and you'll see they're pretty much within margin of error, or at least near as doesn't matter. I even used the figures from the 6s+ to make it a fairer fight.
http://www.macworld.co.uk/review/ip...y-uk-geekbench-benchmark-audio-cheap-3623611/
Geekbench
iPad Air 2: 1823
iPad 2017 Single Core: 2359
iPhone 6s Plus Single Core: 2527
iPad Air 2: 4343
iPad 2017 Multi Core: 4340
iPhone 6s Plus Multi Core: 4407
Same story in graphics performance, all sourced from the above URLs. In fact, here the iPad 2017 pretty much destroys the Air 2 and beats the 6s handily too in the T-Rex test, though can't keep pace in Manhattan.
GFXBench Metal T-Rex Onscreen
Pad Air 2: 41.6 fps
iPad 2017: 56.1 fps
iPhone 6s Plus: 38 fps
GFXBench Metal Manhattan Onscreen
Pad Air 2: 29.3 fps
iPad 2017 Single Core: 28.6 fps
iPhone 6s Plus Single Core: 37 fps
Odd to make such a specific claim that's so easily refuted.
I'd say it's fair to say it has more in common with a 6s.