It wasn't a DHL strike per se, rather a general strike that wasn't very general at all! Typical Belgian efficiency, they can't even make a strike, which is seemingly a national hobby, work. DHL did rearrange the network a bit by routing a handful of flights via EMA and CGN iso BRU, and cancelling a couple. BRU operated more or less as normal. A few people didn't show up, but not enough to stop the show. Italy, and also Spain I belive, were on a national holiday, which of course reduced the number of flights.
What they for striking for or against, I haven't a clue.