This new tax would not apply to all home sales, or to all of the profits from such sales. Like the Obamacare law in general it is complicated and a CPA's dream. The only thing for certain is that you will most likely want to hire a CPA in any year that you sell property.
In any case, it hasn't always been the case that the profits from selling a home were non-taxable. This is a relatively recent phenomenon. Personally I would be OK with getting rid of tax exemptions like this in favor of a simpler code. Tax exemptions like this only exist because of lobbying from realtors and extensions of benefits from those who need it (e.g. people selling their home to go into retirement) to everyone in the country.
Thank you for explaining the 3.8%. I’ve tried to do that several times on FR but it keeps resurfacing. For those interested, here is a detailed explanation from the Natl Assoc of Realtors: