If one is using a glass cage with improper setup, this is extremely correct.
However, this is not necessarily true if you correctly setup a drainage layer, especially in a screen setup. If your substrate is sitting on the bottom of your drainage, then yes it will absorb the water; however if you properly drain this will not happen. Frog vivaria are setup to be completely closed (glass) and 100% humid environments and they can go 5-10 years when properly setup without soil issues (similarly, consider a proper pygmy chameleon setup, same issue); why would our open air setups have bacteria problems so easily? My bet is that 9 times out of 10, the setup is lacking aeration or drainage (ie, it isn't properly setup).
I personally do not mist even remotely as much as some of you (I mist 45 seconds every 1.5 hours) but I have never had these issues. If you are finding your soil to be soggy, try adding 1" of gravel or LECA (hydroton) to the bottom of your planters so that your soil is not sitting on the bottom wicking up the water which hasn't drained yet. If your soil is still soggy, try adding orchid bark or LECA/hydroton directly into your soil mixture; this will increase aeration and drainage.....normally you only want to do this for plants that need more air, however if you are misting very heavily leading to overly soggy soil, this can help your soil breathe a bit better.
The arguments regarding feeders, impaction, etc. are all valid but the OP already clarified that she only cupfeeds so that isn't really an issue here imho.