This can't be true...
I have used wood mounts. As stated, if you do it, build a couple extras at the same time so you can replace it if needed, seal them really well and check them often. I personally won't use them again, but that is just me. There is nothing wrong with them and it worked well. I just felt that it got weaker as it got soaked. I had it sealed, but it still soaked in the cracks. Check it to make sure it is good before you start it and you will be fine.