Why are suggested packages installed by default?

Solution 1:

Recommends and Suggests are different categories.

Your output is showing Recommends (not Suggests).

Ubuntu's default setting is to install Recommends and to NOT install Suggests. Here's how you can see your current settings for yourself:

$ apt-config dump | grep Suggests
APT::Install-Suggests "0";         // 0 = No

$ apt-config dump | grep Recommends
APT::Install-Recommends "1";       // 1 = Yes

You can, of course, change the setting several ways.

The easiest way to do a one-time change is to use apt's --no-install-recommends flag. Example: sudo apt install hello --no-install-recommends

The easiest way to do a frequent change for most folks is to change the setting using a file in /etc/apt/apt.conf.d/