The swf is not something unique to the MC. It is a veeeery old Ayurvedic practice that has been around for hundreds of years. The way the SWF work is that in the proportions that it's mixed it is the same specific gravity as blood so your system won't absorb it.
You can drive yourself nuts if you believe everything you read. I bet it you look hard enough you'll also find some equaly negative alarmist junk about each component of the MC or fasting or about the MC. It's your responsibility and ultimately up to you to do your own research and to consider the source of your info.
The SWF has been around for hundreds of years and the MC has been around for around 50 and thousands have done it succesfully as written with amazing results myself include. Make sure your drinking lots of water and lemonade to stay hydrated and you will be just fine. The one caveat is if you have high blood pressure. I have read of it going both ways, Some have been affected and other with HBP have just breezed right through it. Your call.............................