This perception is simply because the HLG curve stores shadows within a traditional gamma curve. Put simply, the darks are dark. VLOG-L raises the shadows, revealing the noise. Adjust the shadows back to natural a display range, and the noise won't be evident...or at least not more evident than in any other profile.
HLG isn't "better" than a LOG profile. It's just different. I think a lot of people find HLG easier to work with because half of the image is "normal", but it isn't cleaner than VLOG-L, doesn't retain more DR, etc.
When I tested V-LOG vs HLG in a low light high ISO scene using Paul's LUT's to bring them into REC709 I noticed slightly (and I mean slightly) less noise in mid tone areas for HLG and not just the shadows. Again the main reason I use HLG in place of V-LOG is that it uses the whole data range of the codec. Also differences in the shadow areas of both profiles are pretty academic as there is so much noise it's not really a usable part of the image anyway.