This is the article. Wikipedias naive crowd sourced model has been co-opted by the state. I can’t read the paywalled new statesman article but I see from their recent covers that they have an agenda on this issue

https://thegrayzone.com/2022/03/18/bombing-mariupol-theater-...

Edit:

https://apnews.com/article/Russia-ukraine-war-mariupol-theat...

This seems like a pretty well researched account that refutes the false flag idea strongly. The grayzone article still presents some interesting primary sources even when they seem to be wrong here (which is often the case when headlines end in a question mark)

Can’t reply below but your skirting of paywalls isn’t as cool as you think. Pay or read something else. You’re stealing. Also, insulting my intelligence doesn’t reduce my suffering in case you were wondering.

If you can't even get past a paywall, I highly question your ability to apply critical thinking to geopolitics.

edit: Unfortunately, on net, showing the weak arguments of proponents of your regurgitated propaganda to hundreds of viewers does in fact move the needle forward so that we have less of this in the future.