It depends what you compare the ratings with.
Are online chess ratings more inflated then live chess ratings??
They measure different things. They needn't be interconnected. Like FIDE and national ratings aren't interconnected, for example, or chess.com and other sites' ratings, or classical chess and blitz chess ones, etc.
They are certainly inflated compared with OTB ratings, as those are largely produced by Swiss systems where you play people with the same or nearly the same score, or in matches in which you have to play in board order according to playing strength. Online there is much more opportunity to play weaker opponents.
Online ratings cannot be compared with Live ratings i guess it's like compare orange with apples, both fruits but different.
I think everyone have better ratings in online because you have days to analyze your moves, it's very different than having minutes or seconds. Which usually leads to a better moves, ergo better performance.
I believe that the Online (correspondance) chess ratings are much more inflated than the online ones.
I don't know why, but my online is about 300 above my blitz, but I usually take about 10 seconds to make my Online moves!!!