I've heard comments like this, but I can't say I've witnessed it. The pressure used to be on keeping kids from failing because the parents would complain. The school principals by and large took the sides of the parents. Without an outside measure of standards, teachers would pass the kids to get keep them off of their backs. Shame on them, but their pressures were real and unpleasant. At least, those were the complaints I heard from the teachers I knew (and who occasionally opined in more public fora).
When Virginia introduced the Standards of Learning tests (years before NCLB), an amazing thing happened: Teachers were still griping, but they were griping about how they were going to teach all of the stuff they now had to teach. Importantly, their conversations turned back to teaching.
Yes, there is pressure to keep kids from failing. But they simply can't be given a "social promotion" now; they are going to take an exam and will be exposed.
The teachers in the districts where I've been personally involved (via my kids) did something I think was pretty smart: they started getting the parents to sign progress reports and notices nearly continuously throughout the term. In some cases, the parents had to sign off on the assignments as they were give! So there are few surprises at the end of the term. Kind of a CYA move, but with all of the pressures (as you correctly pointed out) they had to do something.
The standards to which they are teaching aren't minimum at all. They are pretty high. My issue with them is that they are not well defined. But I'll save that for another post.
I'll conclude this post with the observation that what teachers are complaining about now is not teaching to the minimum standard tests, but rather that they have to teach to the test at all. They don't agree that what is important is being tested because it's hard to quantify. I have some sympathy for that point of view.