She doesn't seem that bad, guise!
Ok, so I don't care for her personality. She's she's an abrasive type A person from reality TV. That in and of itself is enough for me to not like the woman. But as far as being a mother, she doesn't seem to be that bad.
When TLC first featured Kate and her now ex with their brood, the network was still relatively unknown. The first special about the birth of her 6 little ones was a human interest story, the kind that TLC was best known for showing at the time with narration by a soft voiced woman. A few years later TLC banked on a follow up and found a woman who was quite engaging and comfortable on the camera, with lots of adorable precocious children, and ran with it. It was the very definition of a cash cow! Viewers could not get enough of the kids and took a twisted fascination of watching a couple try to balance this heightened level of parenting with their marriage. This was the start of the turning point for TLC from showing nature shows and general human interest pieces to the grand spectacle it is now. Of course, this meant the Gosselins were making bank as well, enough to give their kids a financially comfortable life at the expense of their privacy. I don't agree with this method of money making, but I can see how enticing it would be to get paid to spend time with your kids with a camera crew in tow; as opposed to getting paid less and working long hours away from your children as a nurse. She did what she felt was the best decision in her mind, and despite all of the public appearances hasn't gone too far to tarnish her image.
Upon watching the latest special where the sextuplets are now 10 and the older twins are now teenagers, they seem as well adjusted as they could be in that environment. They grew up very strict with lots of rules and organization, which may come off as bad on camera, but it seems to have benefitted them. The children have no issue with taking on responsibilities, they are getting good grades in school, and it appears they are socially on par with their peers. They seem happy and boisterous, and completely comfortable with calling Kate out on her shit when she needs it. The TLC money has afforded them a large property with a number of pets and a small chicken farm, and will no doubt pay for college far away when the time comes.
Kate's manner of speaking doesn't seem too far out of line with the kids, though she does have a habit of choosing the wrong words that will make her look terrible on camera. When it comes to punishment, she is neither physically nor verbally abusive and clearly takes the time to explain to her children the reason for needing to pull them aside to have a talk, or taking away something valuable for a short period. She plays up this exhausted put upon mom role for the camera, but it's pretty clear that those kids love and respect her even if their friends call her a "scary mom". I bet she calls out other people's kids on their misbehavior in her house, which probably lead to that nickname.
In interview segments, she confesses things that annoy her about the children and is comfortable with playing favorites, which is typically a parenting taboo. But these are things that I hear from many parents from time to time, and it is always qualified with how much they are all equally loved and adored. She has no issue with telling you which kids are the easiest to deal with, and none of the kids seem phased by it at all. If she chose to not point out the occasional negatives of being a parent, and referred to all of them as angels 100% of the time, she would be scorned for coming off as disingenuous and the B-roll would bite her in the ass. Even Mady, who seems to have been born with a dramatic flare that continues to burn bright, seems to have a good relationship with her hard headed mother. They're definitely not best friends, but none of this seems damaging.
In short, cut the woman a little break. She's unlikable on many levels, but it doesn't really make her a horrible person. It could be worse.