The Clinton/Trump comparison seems extremely dubious, and your quote has a very misleading statement.
Jerrold Nadler, the incoming House Judiciary Committee chairman, at the time declared that "perjury regarding sex is not a great and dangerous offense against the nation."
This seems like a pretty strong argument. I supported impeachment until I found out what actually happens to perjurers.
Putting aside that perjury is a crime for which other citizens go to jail
This is misleading, and the truth works against his underlying argument. People convicted of perjury can be given as little as a fine of a few hundred dollars, OR years in prison, depending on the severity of the offense (see above).
As felonies go, perjury is either a really big deal or barely a slap on the wrist depending on what you are lying about. Based on recent news, it appears likely Trump lied in his answers to Mueller. Depending on what he lied about, this may be NBD or a VBD.