Those studies are small, and short term. Not sure how much stock I'd place in them. Not to mention, how many people take maximum daily doses on a regular basis, consistently, over any length of time to have a negative effect (in this regard)?
Aspirin (but I'm not sure of other NSAID's) break down
connective tissue. The "price" paid for inflammation reduction is that you pay on the back end with ... I like it to "dissolved"
connective tissues.
That doesn't relate to your question about protein synthesis, but it's one way drugs have a bearing on our lifting.
If you read the inserts of almost any drug, OTC or Rx, you'll see an unbelievable list of side effects, many of which can be interpreted to affect lifting and muscle growth.
Interpretation, application, double-blind clinical trials, long-term studies,... a lot goes into the more valuable research, and even then,.....