He means he does not like it when the developers add zombie behaviors to the game that end what used to be a player choice.
Players used to be able to drive around on horde night without any risk. Homing Vultures ended that player choice.
Players used to be able to dig under ground a couple of blocks on any night and be 100% safe. Digging zombies ended that player choice.
Players used to be able to tread water and be 100% safe from zombies. Swimming zombies ended that player choice.
Players used to be able to stand behind 1.5 meter gaps and melee and shoot zombies without risk. Ducking and crawling zombies ended that player choice.
Up until about a week ago players were able to stand on poles and be 98% safe. Pole hitting zombies ended that player choice.
In his mind the developers are taking away important player choices.
Ok, I'll reply to this then (and also reply to the "player agency" stuff). In my own weasely ways naturally
According to the first definition found on the internet player agency is "
The player's ability to impact the story through the game design or gameplay.". If more player agency is needed in 7D2D then I would guess the best way would be some mode where you can clean cities from zombies and they stay that way for a while at least. I don't see agency as an umbrella term or alias for player choice, so lets drop that and stay with "player choice".
A balanced game has balanced options for the player. Invest more work or more ingenious ideas or more skill and you get better results. I don't see where any of above is balanced with the standard method of "building a horde base and defending it".
If you want a horde base where you can afk on actual horde night (in the limits of the game, without "cheats") then you should need to expend more work or build a more ingenious base. But if you can reach that impervious base design with a simple two block hole there is something amiss.
And afk bases are possible. They need lots of steel and a good design, or just lots of steel (and some repair work for continued usage). Why is is it not enough that such bases are possible, why must this AFK-horde night be possible without effort as well, in vanilla ?
If we just sum up choices and call that player choice then yes, a two block hole increases player choice. But is it really a choice when one choice is far superior to any of the other choices ?
Put to the extreme, can we count it as two alternatives if a game lets you choose between getting 1 gold and getting 1000 gold? I would call that a fake choice that does not really increase player choice in a meaningfull way. And it can only work if you tell the player outside of the game that he will destroy his fun if he takes the 1000 gold.
Player choice is a good thing, no question. But please not at the cost of balance, as that is a good thing as well, including balance in the choices the player gets. Unless the game just wants to be a pure sandbox where no balance is needed.