[nossralf]

The described behavior is the default behavior. You can change it to load all tabs after restart in the options†.

To always load all tabs after (re)start, go to Preferences > Tabs and uncheck "Don't load tabs until selected". ("Preferences" may be called Options or something on Windows or Linux, I can't recall right now.)

I would argue this is a sane default setting (it trades some waiting time when switching to a different tab for snappier start-up). Regardless, Firefox gives you the option to choose your behavior, which I would argue is the non-lazy thing to do (however simple).

† Note I am on Nightly, so it's possible this preference is not yet visible in the release version. It probably is, but just to be clear.

[Digit-Al]

Yes, it is visible in the release version.