If you are using a router (i.e. WiFi) to connect to the internet you need to portforward, e.g. external 80 to local 99999, and, ext 443 to loc 22222.
And if you portforward to a different port than your advertised ORPort/DirPort/obsf4 Port, you need to update your /etc/tor/torrc file to listen on LAN IP or listen globally instead of loopback address which ...
...or DIY portforward
Find out which router you have. Log into it. For example I have asus, so i visit: http://router.asus.com/
Read the documentation for your specific router. If you have asus:
Asus specifically states that i need to give my computer a static IP address to portforward for example.
For this ...
Installing addons makes your browser more easily identifiable, therefor they decided to go minimalist on it. Think about it this way: if 80% of Tor users used DDG and 20% used Qwant, by using Qwant you're making it 20% easier to finger print DDG users, and you're making yourself 80% easier to fingerprint by fragmenting the search engine base.
Removing it will put you in the probably less than 1% of people that have done so, making fingerprinting you 99% easier, and honestly, it'd probably make uniquely identifying your computer 99.99% easier because you'd be 1 in 10000 to have removed it and have a specific device with those specific dimensions in full screen.
You are correct, if everyone had these plugins then everyone would look the same.
However, let me share a couple of quotes:
From the FAQ:
Some people have suggested we include ad-blocking software or
anti-tracking software with Tor Browser. Right now, we do not think
that's such a good idea. Tor Browser aims to provide sufficient
privacy that ...