I would not say exactly "karma". A known centre of propaganda and a gathering of people that, not being the army officially, but clearly part of the war effort in terms of spreading mis-information and pro-Z propaganda, and probably directly involved in cyberthreats... sounds to me like a perfectly valid war target.
I guess war is no longer than patriotic and marvellous when you know they can blow you ass in St Petersburg right under the podcaster chairs of the "keyboard patriots division". Alas, it will take many more people's lives in both sides to get to the peace that should have never been broken.
Given how many high-profile individuals Putin's regime killed in elaborate ways (falling out of windows, poison, explosives, beating, disappearing, or just old plain shooting on the street) I'd say chances of "vladlen" falling victim of some MOD/FSB/PMC conflict are higher than Ukrainian conspiracy. Despite being an utter pro-war nutjob he was quite critical of the MOD in particular.
Which would be even better... I mean Ukrainians could do a few attacks like that, but Russian power structures fighting between themselves could wreak much more havoc. Fingers crossed.