It should be stressed that Ukraine isn't attacking WB instead of attacking refineries, logistics, and shipping. They're doing it in addition.

Warehouses are a soft, easy target. And, like oil facilities, you're counting on the goods themselves to do most of the destruction with a little incendiary help. Ukraine has a large supply of slow, cheap suicide drones and this is a good use for them. You force Russia to move air defenses away from the front, absorb economic and financial losses, and remind regular "non-political" Russians that they're at war. Also, you minimize collateral damage because unless workers are killed in the initial attack, they're likely to escape the conflagration that accounts for most of the damage.

They are creating a new marketplace for dual-use goods that were previously, albeit with limitations, traded on WB: https://theins.press/en/news/296020

soft targets are the way.

The "online retailer" also provides logistics services to the Russian military.

The attacked OnlyComrades?

Russia Strikes Epicentr, Nova Poshta, Silpo, Novus Warehouses, Killing at Least 10 (kyivpost) - retaliation for the Ukrainian strikes. Russia apparently also claims Nova Poshta became a logistic arm of the Ukrainian military.

I was hoping to find some recordings/archive of the Wildberries SMO section from before they removed it, but no luck. The best I could find was a reddit thread with some examples from a month ago: https://www.reddit.com/r/UkraineWarVideoReport/comments/1uzsxn9/a_huge_amount_of_military_goods_are_sold_on/. Camo bulletproof vests and equipment for fiber optic drones.