Your camera collects "raw" data. To see it as a picture it has to be interpreted somehow. Everything from your camera preview to Olympus software, and even Adobe's, takes a first guess preview. Olympus may choose to obliterate the inherent noise from the sensor. Adobe may choose to leave that to you with your control over a variety of sliders. Besides the six sliders under Noise Reduction, there are more with Clarity, Luminescence, etc. There is even the new DeHaze slider.
Then you have marketing, where someone has to say mine is better than yours.
I don't think there is any question that Lightroom, and Photoshop, try to leave the interpretation to the user more than try to automate it with a preconceived notion of what it ought to be.
Assuming you are shooting raw files, the reason probably has something to do with Adobe needing to reverse engineer the software needed to interpret the Olympus raw files. Olympus knows how to best interpret the raw data and how to read and apply the camera settings to that raw data to give you a first view that looks like it did on the back of the camera. Adobe makes no attempt to read any of the camera settings and applies its own profiles to the data for Lightroom's initial viewing of the files.
As a general rule, the best raw interpreter for your cameras raw files is the interpreter from the camera maker. Unfortunately, the camera maker is usually quite bad at making software and wraps a rather poor editor around that great interpreter. Adobe makes really great editors, but all of its raw file interpreters may be second best. The differences between Adobe's interpreter and the Olympus interpreter is open to debate.
Is the Adobe raw file interpreter for your Olympus camera good enough for you? Only you can answer that. My guess is that while the Olympus raw interpreter might be marginally better, the Adobe editors will go well beyond making up the difference.
my em1 gets noisy between 800 and 1600 ISO. I shoot raw+jpeg. I purchased this em1 about 60 days ago. In June of 2015, I rented an Olympus EM5 Mark II to test, in October I rented an EM1 to test it. Neither of these two rentals had noise that I have in the EM1 I purchased. The Olympus tech support rep also told me they do not have Lightroom or Photoshop to test with, so their research seems a bit limited to be saying that the problem is Adobe and I should use Olympus View 3. Just some more information. Thanks for your input.
I am shooting Raw+jpeg. I agree that Adobe is much better than Olympus software, but it shows noise that Olympus says may not be there. I said I would never have bought the EM1 to them if I had known that their Raw files were correct in Lightroom and Photoshop. I may need to understand better the Lightroom ability to help this situation, but that means I may have to have a preset or develop each picture from the EM1. That is something I would prefer to avoid. Thanks for your input