Honestly?
This sends up red flags to me. This suggests (and it may certainly be not true, only suggests) an inflexible DM who is opposed to new ideas and, frankly, if the DM is either incapable of adding or unwilling to add something as simple as a new race to a D&D game, what else is the DM going to be inflexible about? If I want to pursue some goal for my character, is the DM simply going to veto that because it doesn't make sense to him or her? If I want to play my character in this or that way, is the DM going to object because it doesn't make sense to him or her? Where does the line get drawn?
Now, this might totally be a non-issue. The DM might be perfectly fine. But, having been bitten by this sort of thing far too many times in the past, where overly controlling and overbearing DM's have tried to justify their actions by claiming setting purity, I would be very leery about joining the game unless I knew the DM from beforehand.
In a totally new DM? That I'd just met? Yeah, it would likely result in my thanking the DM politely but declining to play. Sorry, but, I've just been bitten too many times by this.