There are lots of similar articles, it is part of the canon for foodies today. Some of the pro-oil lobby sell board oil, others pass it on as received wisdom from old cooks. They may be right. Or not. Unlike the question of wood versus plastic boards there does not seem to be any studies available on either the cracking or health issues re oiling.
On the two (or more) boards for different boards if I was in a commercial situation or anywhere that a board could be left with meat juice on it I would adopt the system. As it is my board is very carefully scrubbed, rinsed and dried after any protein is put on it. This system has served me well for a long time.
On contamination I have a little story. All true and it happened to me. I had just finished doing a big banquet for a charity do and I was tired and frazzled and looking forward to sitting down for my dessert and a glass of wine. I realised that I had served the dessert without the garnish, which was sliced feijoa (pineapple guava). So got the dish of sliced fruit and went round the room and offered it to those who wanted some but I had forgotten the serving spoon. Most took some, a few refused as they didn’t like feijoa, or wouldn’t try it, but one looked at me askance serving with my fingers. He diffidently said he would like some but only if I got a spoon. So I got the spoon and he was pleased. I then mentioned that if my standards of food slicing and hand washing were not up to scratch he and the all the rest were going to be very ill the next day as I had personally caressed everything in every dish. He looked like he might not eat his dessert but I said he may as well risk it as he had already eaten the rest.
This is not to say that no wooden implements benefit from oiling or that all wooden implements benefit from oiling. On cutting boards I am forced to leave it as an open question until better data is available.