Maxperson
Morkus from Orkus
There is a druid in the 5e Monster Manual Appendix B: Nonplayer Characters. None of the other NPC names are class names. For example there is an "archmage" and "mage" (both with wizard spells), but not a "wizard"; an "acolyte" and a "priest" (both with cleric spells), but not a "cleric". This suggests that the NPC names in Appendix B are terms used in the game world. We can therefore conclude that "druid" is both a rules term for a class and a term used in the game world. The lizardfolk shaman casts druid spells. There would therefore be no difficulty in calling the lizardfolk caster a druid.
That's a faulty assumption. Archmage and mage are just alternative names for Wizard, as Acolyte and Priest are alternate names for Cleric. A much stronger assumption is that those NPCs are Wizards and Clerics. Just as an Assassin is a Rogue and a Berserker is a Barbarian.
It's not hard to see that NPCs can have alternative subclasses that are not allowed to players.
Why then is the lizardfolk caster a shaman? Because "shaman" is only used in D&D to refer to NPCs and monsters, not PCs. It does not appear in the PHB. But why should the word be used in this way?
No. The Druid can be a tribal Shaman, and therefore a PC Druid can also be a tribal Shaman. I mean, would you say no if a player wanted to call his druid a tribal Shaman? I certainly wouldn't. Hell, I wouldn't even say no to a player calling his Cleric a Shaman.
Lizardfolk live in "swamps and jungles". Europe is not known for its jungles. They lure trespassers "into the lairs of crocodiles". Crocodiles live only in hot climates - the tropics and subtropics. Lizardfolk eat and sacrifice sentient beings, tropes which have, over the last 300 years been attached largely to non-Europeans, especially sub-Saharan Africans, Native Americans, and Pacific Islanders. According to TVTropes the Cannibal Tribe trope refers to "dark-skinned, non-Christian native tribes".
Europe isn't known for it's Treants, Aboleths and much more, either. You're stretching things beyond credulity in order to try and divorce Shamans from Druids and it doesn't work.
No. They're not. And neither are any other races, classes or monsters..............unless you homebrew a fantasy D&D Europe campaign, in which case Lizard Folk are European.Lizardfolk have shamans instead of druids because they’re not European.