Interesting change, making it a construct.

So does it get to make two actions on one turn? because this could kill my wizard before he gets to even attack

So has the lore around them, changed now that they're a Construct and no longer a part of the "natural" order (or as much a part as a monstrosity is)? I understand people take one look at it and think "why is it a monstrosity, it should be a construct", but has that come with any lore changes? I understand why that change was made and while I'm not a fan, I don't want to come off as if I'm just complaining (because I do agree with some of the monster re-categorisation, namely those moved from monstrosities to celestials), I just want to understand the lore implications of this change. Who makes these and why? Is it for protection? If so, is it easier to create than a golem, which from my understanding can take multiple days spent just working on the golem?

Also, what are the lore implications of creatures (like gorgons, nagas and sphinxs) changing monster types in universe. Is it an in-universe change or just an out of universe one. I ask because monster type isn't just a bit of categorisation, since it interacts with many spells, like how constructs are immune to many effects that can effect a monstrosity and how spells such as Protection from Evil and Good affects celestials but not monstrosities (why are nagas suddenly affected by this spell but not before) so its a bit harder to justify than "a number of our top rangers looked more into gorgans and found they aren't birthed, but constructed by some mad lad in that tower, so please go and kill him. Oh, and our theories have been proven correct, the nagas and shinxes are celestials, so we can take them out of their temporary position in the what-ever-else-there-is-besides-the-other-categories category and finally place them in celestial."

I'm I possibly putting too much thought into a change that may not be in-universe? Maybe! Its likely in the same why that spellcasters like archmages don't have the regular spellcasting ability of 2014 or the wizard's spellcasting in 2024, but instead have what is essentially innate spellcasting with the innate part removed as they still need to cast with material components. Its an out of universe change that does effect mechanics. Still, its a discussion I would like to have with other players who may know the new lore better than me.

I'd primarily think of it as an out of universe change. Like you said, so many creatures changed categorization that there would have to be a huge event for spells to suddenly treat them differently. Whether they change within an existing game is up to the DM and players.

To be honest, this is one of the changes that seemed less necessary. It seems like it was inspired by the way artists have been portraying them (more plates of iron than iron-ish scales) than from lore. Gnolls going from humanoid to fiend maybe isn't necessary, but their creation lore is a solid argument for the change. It could also be that the WotC team thought we could use more constructs (which would make sense to me). Fortunately it's a super easy characteristic to revert in a home game if you want. And easy enough to have "natural" monstrosity gorgons appear in the wild and also construct gorgons protecting BBEG's lair.

Thank you for your input. I appreciate it.