Yes, just about always.
And if you're a copywriter who thinks you don't... you're in denial.
Let's define the term:
Manipulate: Control or influence (a person or situation) cleverly, unfairly, or unscrupulously.
Here's proof of my contention...
When you write copy, you accent the positives (benefits) of the product AND you mitigate (if you mention them at all) the negatives of the product.
That fits the above definition.
Not trying to condemn anybody, but hey, let's get real.