The Yuan-Ti Pureblood playable race has the Innate Spellcasting trait, whose description states (VGtM, p. 120; emphasis mine):

You know the poison spray cantrip. You can cast animal friendship
an unlimited number of times with this trait, but you can target only
snakes with it. Starting at 3rd level, you can also cast
suggestion with this trait. Once you cast it, you can't do so
again until you finish a long rest. Charisma is your spellcasting
ability for these spells.

Can the Yuan-Ti Pureblood's suggestion spell from this trait only be used to target snakes?

I was under the impression that only the animal friendship spell from this trait was limited to only being able to target snakes, while poison spray and suggestion could be used as stated with no such targeting restrictions.

However, I've run into a DM in organized play who is arguing that suggestion is limited to snakes only, and I cannot find any official text anywhere clarifying this.

It doesn't make much sense to me that suggestion would only work on snakes when suggestion requires the target to understand you. Outside of special circumstances, most snakes would not be able to understand you as a Yuan-Ti… The animal friendship part of this ability is the only part that lists this restriction, and it seems to only restrict that spell rather than the entire trait. Otherwise, it would also imply poison spray could only be cast on snakes, which is just silly from both a canon and utility sense.

Despite my arguments against it, this DM seems set on his ruling unless I can find something official stating otherwise. Anyone know of any references to this ability I can show him?