No, it's just shitty behavior. Again, no one is hoarding anything. You might have a point if they had set up paywalls behind chapters or asked for donations, but this is clearly not the case. Sniping active series of groups that deliver good quality releases with half-assed releases is just spitting on their efforts.
Some groups may engage in the scan war then because they genuinely want to keep working on the series, but it happens just as often that they drop the series entirely because the motivation goes down drastically.
This series gets regular releases and looking at the schedule for the official release, you would get a volume every five months. Or in other words, if you are unlucky, the sniper also loses their motivation quickly and then you may have to wait years to see how it continues. There is no good reason here to snipe.