Using a different tool to create a bootable drive is just a part of installing any operating system, not just Linux. If you ever need to install windows on a pc that doesn't have it installed you will see the same process.
No the episode is definitely a commentary on racism. The inhabitants of Finetime are not just gen z, they are explicitly upper class gen z. They have literally blue blood. They are very Tory-coded.
The whole episode is riddled with micro aggressions from Lindy towards the doctor. Here is a possibly incomplete list of them:
declining the Doctors call in the cold open. but taking Ruby's later on
suspecting the Doctor is responsible for the situation
being disgusted by Ruby and the Doctor being in the same room
not noticing the Doctor and the person calling her in the morning where one and the same, saying she just thought they "looked the same"
Introducing the Doctor to her friends with the words "he is not as stupid as he looks" and suggesting he would be punished later on
There is also the mention of a cleanse, which takes on a very different meaning after the twist especially since not just the majority of the Finetime characters but all of them are white.
The whole episode is designed to make you question your own perceptiveness of racism. After the twist you are supposed to go "how could I have been so blind?". I recommend a rewatch. And no, I didn't pick up on it at first. I did notice some of them as weird, but noticed what all of them have in common only at the end.