Because when you say "Oh yes, I remember! I remember it very well. As if it happened yesterday...", etc., well, then you are doing the remembering right at that moment. So this is actually a present continuous event. And in Turkish you can actually express it using the present continuous tense. How weird, right? :)
There are many similar situations in English where we use the simple present to describe a present continuous event. I do, I want, I understand, etc. I just want to go home. I may be wanting all day without interruption, yet I still use the simple present. Turkish uses the continuous: Eve gitmek istiyorum.