It only applies to investment property. If you own your home the first 250-500k of capital gains is exempt depending on your filing status. 1031 exchanges are a decent amount of work and have some additional requirements (it's not really for house flipping). They are also a tax deferral strategy. The tax eventually comes due.

1031 is not for properties the owner lives in. For owner occupied properties, there is a $250k per taxpayer exemption on gain if requirements are met.

As I understand it, it's possible to use both rules on the same property, but it takes many years and specific facts.

Flipping houses usually means buying a house -> making improvements to the house -> selling it for a profit. I wouldn't call that "speculation".

Speculation in this case could just be buying a house and trying to sell it for a profit later without improving the property.