And getting +100 unity per month without any pops is massive. The base unity output of bureaucrats is +4 so executive vigour produces as much as ~20 pops (if you account for bonuses, without any bonuses it produces as much as 25 pops). Spamming this building is roughly equivalent to gaining 20 pops per planet! This is absolutely op.
This is a terrible analogy. Literally nobody spams bureaucrat jobs to build unity in the early game. Nobody's got the pops for that. The first building a serious culture planet will have is a monument, which right off the bat adds 5% Unity per tier of the building, and that's going to be on top of stuff like high stability, governor levels, general production bonuses, etc.
If we take a more serious look at Unity production in the mid-game when this building *might* be relevant, a max-level Unity building will have 6 jobs producing base 5 unity each (because we're not daft and we're building an Orbital Filing System). These jobs will then have a +25% bonus, minimum, from techs boosting resource output, a similar 25% bonus, minimum, from ascension-based production bonuses, another 25% minimum from high stability, another 12% or so from a Governor, 5% from Planetary Unification, 15% from an upgraded monument, some number of random 5% or 10% bonuses from events, anomalies, and situations, and also likely a few more 10% bonuses from traditions and AP's like Prosperity and/or One Vision. Finally, if you're actually going to build a Unity planet then you're building it on a planet with a misc. bonus like Wenkwort, which has a 40% bonus, Paradise Made which is 25%, a planet with The Sentinels which is 25%... there's a lot of options, there, and that's not even all the bonuses available.
Getting 10 unity per Bureaucrat in 2250 is not hard, so it's not 25 pops, it's *maybe* 10, but you're also losing out on the specialized job production of a better building for the planet if you decide to shove these on every planet in the galaxy, and that's a terrible idea, you never build this over a fully upgraded Tech Lab or Commerce Megaplex on a planet built for purpose, and planets doing basic resource production will have plenty of other, more practical uses for their relatively limited building slots such as housing buildings, amenity buildings, refineries, maybe some defensive buildings to double as a fortress world, and maybe some trade buildings. That's also just a rough stab at what can be done at mid-game. Once you're all the way into repeatable techs getting 13-14 Unity per Bureaucrat is not all that extreme.
Compare that, instead, to the Vultaum Reality Computer. It's basically a second Research Institute -- your researchers will produce 17% more reasearch in a way that works multiplicatively with the Research Institute and other Research bonuses -- basically a better modifier for a slightly worse job on the building itself. That's a crazy good building that always gets built on any remotely research-oriented planet as soon as possible.