First, I said that there isn't a Constitutional check on lying. Libel and slander are more than just lying. Second, on your points, then there should have been a qualifier in the First Amendment if that was the Founders' intent. Or, there should have been scores of such cases from the early period of the nation. But there isn't, and there aren't. Indeed, Jefferson's quotes on how much he detests the press' lies, compounded by the fact that he never sued anyone on libel grounds, support the assertion that libel and slander, while detestable, aren't banned forms of speech. Now, to be sure, there are such cases but the bar is high.
Smith v. Minor, 1 N.J.L. 19 (1790)
Austin v. Hanchet, 1794 Conn. App. LEXIS 66 (1794)
Fowler v. Collins, 1795 Conn. App. LEXIS 51 (1795)
Whittlesey v. Dickerson, 1795 Conn. App. LEXIS 101 (1795)
Respublica v. Cobbet, 3 Yeates 93 (1800)
United States v. Cooper, 25 F. Cas. 631 (1800)
Hersh v. Ringwalt, 3 Yeates 508 (1803)
Hook v. Turnbull, 10 Va. 85 (1806)
COOK v. BARKLEY, 2 N.J.L. 156 (1807)
I could go on and on and on. There are more than 28500 cases involving defamation in just one database.
Your assertion is patently absurd. The First Amendment doesn’t protect defamation even today, EXCEPT to give extra-constitutional protection when the defamation is about a person that the press has converted into “public figure” or when said defamation is about a “public official.”
The nation’s defamation laws worked fine prior to NY Times v. Sullivan and the standard prior was workable and appropriate.