I get what you're saying, and generally speaking I completely agree. Don't think you'll find a single person anywhere who thinks reaching for a high risk defenseman is a good idea haha.
However, I don't think Kirsanov fits that description. If anything he seems like a safe pick high floor low ceiling type of player. There's a very good chance he ends up a solid all around 2nd paring LHD in the NHL, with potential for more. He has good size and plays a solid all around game that coaches love. It's super impressive that he held his own very nicely in 29 KHL games as an 18 year old, not many guys can do that at that age.
Not saying we necessarily SHOULD draft Kirasanov at 16 overall, but I don't think he would be a big reach there. He's been a riser in some rankings I've seen...FWIW Pronman has him at 16 in his prospect rankings -
Top 151 Prospects for 2021 NHL Draft: Owen Power leads Corey Pronman's final rankings
All that said, I have no problem going with a higher upside forward or any other position in the first round!