I guess that these could be up for interpretation, but to me, it's pretty clear what these tweets mean:
So someone told me that *I* said the two remaining LI's are the race-gated ones. An odd thing for me to say, seeing as it's untrue.
Look at the way the second sentence is worded. It's pretty clear that the "it" refers to "the two remaining LI's are the race-gated ones" and not "my saying it". Substitute either of those phrases for the "it" and see what I mean.
"An odd thing for me to say seeing as the two remaining LI's are the race gated ones is untrue". (Makes sense)
"An odd thing for me to say seeing as my saying it is untrue" (Doesn't make sense)
You forgot to add this continuation of the tweet:
Random-dude: so this means that the 2 race gated romances are romance options we already know about? Cool.
David: No, it does not mean that either. Seriously, stop putting words in my mouth.
Point of the matter is that David has said nothing he and has confirmed nothing, at best what he said is that one 2 of the 8 option would be gated, that it, it could be 2 of the known LI's, it could be the last 2 LI's or it could be a mix of the two.
The continuation of the tweet then addresses the other side of the pendulum swing. When people thought that his first tweet said that neither of the two unannounced LI's were race-gated, he corrected them by saying that it doesn't mean that either. This one doesn't confirm anything really.
What it leaves us with is the fact that both of the remaining unannounced LI's are not race-gated. And we know that IB and Josephine are not race gated. So the two race-gated ones are either Cullen, Cassandra, Dorian, Sera, and no more than one of the two unannounced LI's.