The easiest answer, of course, is that they are two different ships, and that someone doesn't understand the definition of a word.
They are two different ships. But also, they consider Titan-A a refit of Titan.
It is the easiest answer because... it's the answer.
If what you're trying to say is that Titan-A isn't a refit, that's objectively incorrect. The show confirmed it as a refit of Titan. There's not really any discussion to be had on that fact.
The discussion is more the circumstances being the Titan-A being both a new vessel and a refit concurrently.
I don't, but that's me. I spend a lot of times doing research on many different things to find the most satisfactory answer. To me, a refit has a specific definition. Saying "words change meaning" isn't satisfactory because we have no way to verify "refit" changed. We assume it did.
And yet, we circle back to the objective confirmed in the show that the Titan-A is both a new ship, AND a refit of Titan.
I would think the easiest answer of them all is to just accept that the word "refit" isn't applied in the exact same way as one might use the word today. It's not uncommon for words to drift in meaning over several centuries.
Vs. if I can find instances that support this idea I find that more interesting, and I learn something. Win/win. Call it hoop jumping; I just call it research
I can appreciate that, but in this particular case it seems like the "research" is trying to desperately to disprove an object canon fact. That just seems so counterproductive.
It's so much more reasonable to take the established the facts and extrapolate from there, those facts being that Titan-A is a refit. Confirmed by canon. 100%. Titan-A is also a new ship. Confirmed by canon. 100%. Those two items are irrefutable. So my research would lead me to explaining how two statements could be true at the same time, because we know that they are.
Yup. The line is an odd one to me. It's why I'm far more forgiving of things in Trek because I've seen the heretical talk for over ten years now (originally aimed at Enterprise and then Abrams) and I'm like, "Shouldn't we just be enjoying this show?"
Apparently not.
I think a part of enjoying the shows are the discussions about them, and especially in the case of Trek, the minute details. Although I come from the angle of not trying to explain
away things as if they didn't happen, but trying to explain them as they did happen, even for things I don't like.
For example. I truly despise the Discovery Klingons. But... they exist. My eyes can confirm that. So rather than trying to come up with some esoteric explanation that basically says "actually, they don't exist", i'm going to explain how they do.
To piggyback on the Defiant example, I think it might be safe to assume through observations that Starfleet doesn't operate on a "standard procedure" for everything. My observation would lead me to believe that many of these decisions come through local command... the decision on if a ship with a previous namesake gets a letter suffix or new registration seems to be up to local command.
Defiant is the strangest outlier in being the same class of ship, the same name, AND the same registry. The only other similar example we have is 1701 to 1701-A, which seemed to similar circumstances but it got the suffix.
If we are going to speculate, and make it relevant to this thread, I think that the Defiant situation is actually something of a reverse Titan. Sao Paolo may not have been completed yet, and Defiant was salvaged enough that alot of Defiant went into Sao Paolo. Makes sense in this situation moreso than most, they were in a desperate war, why waste working components? So in the end given that the ship was built/completed with Defiant parts, and as a way to honor it, they treated it more as a "rebuild" of Defiant rather than a new ship or a "refit".