Name of argumentation in a discussion

Some weeks ago I was discussing with a friend. I criticized Trump about something and then my friend replied "OK, but what about Obama?". This question was aimed at removing attention from Trump and discuss about something else, which, albeit relevant, was not the main topic of the discussion. Moreover, my friend was assuming that I prefer Obama to Trump, which is not necessarily true (I might dislike them both). On top of that, he is not really saying that what Trump did was correct; he just said that Obama did it too.

What I would like to know is: what is the name of this argument and how do people usually handle it? This kind of argumentation is used a lot by politicians, e.g. when criticized about something, they reply saying that the politicians from other parties did similar things (just like my friend did).

This question might not be suitable for this community, so I will apology in advance if that’s the case and I will erase the question, but I didn’t know where else to post it.