It is common nowadays that the media call Muslims with labels such as fundamentalists, extremists and terrorists and many Muslims start apologising. Well, actually a different approach is needed.
The meaning of fundamentalist is "someone who follows the basics of something". Therefore, to be a good English speaker you need to follow the fundamentals (basics) of the English language and someone who follows that is a fundamentalist. Similarly, being an Islamic fundamentalist means that you are following the basics of Islam and there's no harm in doing that so no need to apologise for being a fundamentalist.
As for extremists, every Muslim should be an extremist. Islam teaches peace and love so a Muslim should be extremely kind, extremely merciful and so on. Furthermore, no one should stop you from being such an extremist.
A terrorist is someone for who terrorizes someone. For example, when a robber sees a policeman, he is terrorized and therefore, the policeman is a terrorist for the robber. Similarly, a Muslim should also be a terrorist for anyone who does something bad such as stealing.
And if every Muslim is a fundamentalist, extremist and a terrorist, the whole world will become peaceful and very few crimes would be taking place and that is exactly what we want.
Note: You will find more options there on the top right corner, inshaAllaah.