The plaque that lines the blood vessels might be analogous to soap scum.
One can find almost any point of view to support pre-formed opinions on the Internet. You can even prove the earth is flat by citing certain Websites.
My preference for distilled water is experiential. I would not force anyone else to drink distilled, but nobody is ever going to convince me I am going to an early death. The hard spring water I drank for twenty years was causing health problems including calcium deposits in my lungs and stiff and sore joints.
Filtered tap water is not ideal either. If you read the fine print, common filters do not filter out the chemical chlorine, just the taste. A potentially more serious problem is that charcoal filters can harbor bacteria. A filter must be changed regularly. Filtered water can lead to infections under certain circumstances, care must be taken to keep the filter, and the surroundings as clean as possible. Charcoal may attract and hold contaminants, but it is not antibacterial.