That is versus that was in the following sentence

Hello, I'd like to post a quick question concerning the use of present simple versus past simple in the following sentence:

"Magic! So that's what it felt like! No wonder that wizards didn't have any truck with sex!"

How come we use "that is" instead of "that was" in the following sentence.

I can only see it as a matter of stating something that is still a fact. However, I'd be very grateful if you can shed some more light on the matter so that I can understand better.

I've also looked up another topic whose author posed a similar question:

For the sake of brevity, I will be quick. Here are the sentences examined in his topic:

1.That's what we thought
2.That's what we had planned but it didn't go through.

And here are my explanations:

In both of case of 1) and 2) the present simple (is) refers to something that happens now - i.e. one of the interlocutors expresses an opinion at the moment of speaking. For instance:

A:John is back? I thought he was never coming back!
B:That's what we thought.

I.e. the "is" in B refers to the whole A statement.

CalifJim did mention back then, that there had been a similar topic here, but I was unable to ferret it out. If you could please either provide a satisfactory answer to my queery or refer me to self-study guides (or the topic mentioned by CalifJim) I will be very greatful!