I tend to side with NASA on this, although it's hard to really decide with this scant amount of info.

However

There probably just aren't that many choices available. There are only so many high tech companies, and only so many really qualified experts.

Also, while everybody wants their company to do well, they're certainly not going to bless a design that has significant risk.
EVERYBODY knows who made the bad O rings. A failed mission leads to some intense analysis -- and woe betide any company that even appeared to have conspired to sell a faulty design.

Not only that, there are several companies involved. They may not all be experts in all areas, but all the folks involved will be paying attention to see that nobody is fast tracking something through.

Finally, there are the people themselves. They have to be tech weenies are qualified to do the job. Tech weenies are naturally objective. They train for years on scientific rigor. Also, believe it or not, most people want to do a good job.

I would also like to rant on politicians and NASA hers, but I won't.

It's too bad our government doesn't have a better watchdog organization to ensure those who hold the highest offices in our country don't have "Conflicts of Interest". Bravo NASA IG, BRAVO! We don't need another self-licking ice cream cone.