It was noticed that there was something off about explosions, though. That's why it was slowed down; to show oblivious devs/testers what they missed that is noticed by the general public. It's not about "offense". It's one of many small aesthetic problems that add up to obviously odd-looking, unappealing animations.
It's understandable that devs and testers looking at the same gameplay for a long time will become used to its problems and become unaware of them. That's why public testing is so helpful.
Edit: I believe a large reason why most 2D Worms games made after the 2nd-generation games have not been as successful is because of the comparatively unappealing aesthetic. Aside from OnlineWorms and WWP Aqua, Worms games have looked worse after WWP, with their lockjaw mouths, strange backflip animations, screen-shaking explosions, and pointy outlines. The way they roll matters. The way they fly through the air matters. It all adds up in presentation, and it affects impressions of customers.
Side-topic: When I was first playing WA, I wanted to draw worms. They looked so simultaneously cute and cool. I can't say that about the later worms. Look at your avatar, Jonno. Does that really look good to you, with the giant teeth and the lockjaw non-smile; mouth stretched to the bottom corners so hard it looks painful? I think that the look for worms was ruined forever since that kind of design.