Zelensky let them all out when the war started[0], including the infamous Tornado battalion[1][2].
"have a long and proven track record of lying without any shame or remorse"
Just like the Ukraine or the US.
"which Russian side ... encouraged"
Another fine example of 'atrocity propaganda'[3] to mobilize public support in Western countries for the Ukrainian war.
"vs silence on Russia using all sorts of forbidden weaponry"
So why is the silence? That happens when things get investigated and no proof is found. I remember Ukrainian general claiming in 2014 that Russia used a tactical nuke in Donbass.
[0] https://www.dailymail.co.uk/news/article-10559879/Zelensky-r...
[1] https://www.rferl.org/a/ukraine-tornado-battalion-rogue-para...
[2] https://focus-ua.translate.goog/uk/amp/ukraine/521825-osuzhd...