With the latest version of Safari, Apple removed from the right mouse click* contextual menu the ability to create a new tab. So instead of "right click, select the top item on the menu, left click" the only way now to create a tab is to either use the file menu or keyboard options. The contextual menu option of creating tabs has been like that for years and years and was not broken and I knew of no complaints about it. Removing it would have been a deliberate action that as far as I can see serves no purpose as the right click contextual menu still exists. And to add insult to injury the item that is now on the top of that list is "close tab", so every time my muscle memory kicks in I end up closing a tab I was viewing rather than opening a new tab.
* Yes, you can use non-apple mice with apple computers, and yes the right mouse button does work. And in general I dislike using Apple's mice and only use 3rd party mice (And Microsoft makes good mice and keyboards that I like and use as does Kensington)