It's understandable that the article would arrive at that conclusion re: mycoplasma pnemoniae and chlamydia pnemoniae. The more I read about various mycoplasmas, the more I find out that probably the majority of doctors are not too familiar with them. I believe this is because they are difficult to test for (although not impossible). I think they tend to get overlooked because symptoms can be easily diagnosed as more common conditions like asthma, pnemonia, etc., without a pressing need to test for mycoplasma. However, if you look up the various types of mycoplasmas (ureaplasma article lists many forms) in the same journal you quoted, they are present with rheumatoid arthritis, PID, infertility, urethritis, cervicitis, bronchitis, and pyelonephritis. That's not to say that they are always involved in these conditions, but certainly that they may be involved.
My mycoplasma infection came with my tick bite. I never had respiratory symptoms prior to that. (I was diagnosed with asthma within 6 months of the bite). That is not the only way a mycoplasma infection can be acquired. It took 15 years to get Lyme and Babesios diagnosed, and 16 years to get mycoplasma diagnosed. No one tested for any of it for that long, despite seeing 12+ doctors in that time.