SMLLC double-taxation self-employment tax

w.r.t. this article: https://www.nolo.com/legal-encyclopedia/self-employ[product key removed]s-single-member-llcs.html

 

author clearly states: Self-employment tax is separate from, and in addition to, the tax you pay on your gross income.

 

so then with a SMLLC and using pass-through taxation, if I run a business and the business makes a profit of $100,000 then:

 

1. I have to include that $100,000 as part of my normal income on 1040 (this is by definition of pass-through taxation) and pay taxes on it.

2. Not only that I have to pay self-employment tax on $100,000 

 

Question 1: is this correct?

 

Question 2: is this not double-taxation?

 

Question 3: if I were operating as a sole proprietor, do I still pay the self-employment tax? If not, then I am at a tax advantage operating as a sole-proprietor vs SMLCC