The highlighted section of that link reads as follows:
The research found that putting the toilet lid down reduced the number of both visible and smaller droplets during and after flushing by 30-60%. However, use of the lid also increased the diameter and concentration of the bacteria in these droplets.
The article doesn’t indicate whether the total bacteria contained in the now larger and more concentrated droplets is thought to be comparable to that contained in the full spray of open-lid droplets, which means a precise comparison isn’t available, so technically I guess it could go either way. However, common sense tells us that many of those microorganisms will either get stuck to the underside of the lid or fall back into the water, so it seems nearly impossible that closed-lid flushing could spray 100% of the microorganisms that open-lid flushing does, right? So if the best (seemingly unlikely) scenario for open-lid flushing is that maybe it only sprays the exact same number of farticles into the air, then what’s the appeal?