I've been a JW for years and years... Never once did I rejoice in the
misfortunes of anybody. That is an individual characteristic, not a
religions. You will meet people that are good and bad anywhere. Judging
an entire group of people based on individual actions is bias and
elementary.
As a former Bethelite and lifelong JW, I agree with the above reply for the most part however I think there is still a lot of truth in the premise of the original post. The JW's who make these unloving comments, more often than not go unchallenged by the JW's around them . JW's have been trained to look down on "the world" and have condemned (in their own hearts and otherwise) virtually everyone (except themselves) to a horrendous death in the very near future and they look forward to the day it will finally happen. They claim to be going from door to door out of love of their fellow man but sometimes the comments made in the car groups about the householders are often far from loving and demonstrate that they are really out in the ministry to save their own skins rather than to accomplish anything of a humanitarian nature. They often refer to householders who don't take the magazines as "goats" and they make covetous comments about living in their nice homes after Armageddon since they've decided in their own minds that the occupants, unlike themselves, will have been destroyed . Some JW's are so conditioned and immune to their judgemental view of non Witnesses that they don't seem to view the occupants of the homes as real people deserving of compassion and find it easy to be callous about them and pigeonhole them all as doomed
As you say, it isn't fair to judge an entire religion based on the actions of a few but I do have a problem with the way Witnesses hesitate to correct these unkind comments against worldly people for fear they will be looked upon as sympathizing with the world. The literature they leave with interested ones, is full of hateful comments about entire religious groups based on the actions of a few of their members of their leaders and in view of this, it's a testament to the people of the world that the Watchtower and Awake magazine are even still in existence (for now).