I agree with you, Deejay, but I think the white foam - which is like mayonnaise - is an emulsion resulting from water in the oil and its presence increases during short runs in the winter, when the water is formed as a by-product of the combustion but is never boiled off because the engine and the oil never get hot enough.
I learned about this is April when I went on my first long run on a freezing cold day, after a month or two of more-or-less daily short runs in cold weather. The pipes to and from the engine became clogged with this stuff (or they were clogged before I started) and I lost a lot of oil through the air-filter in the toolbox as the whole system became blocked on that long run. There was a lot of water mixed in with the oil remaining in the toolbox afterwards. On that occasion I changed the oil (some water came out first) and cleaned out the pipes. However the can itself was empty.
Now that I'm getting in some longer runs in better weather, there's no emulsion in the pipes and none visible inside the filler-neck. My most recent oil-change (last week) showed no oil in the water, either, and this is why I think the two problems go hand-in-hand.
Mind you, I think there are other worrying things being recirculated through the system via the catch-can - other by-products including acid. It doesn't seem a good idea to let these back in if there is an alternative. (But I wouldn't want to spray that acid out over my chain, either).
Tom