My guess is that they used the (still spurious) excuse of trademark infringement, since it uses "spotify" in its name and you could plausibly argue that consumers would be deceived into thinking it's an official spotify site. Most would probably realize it isn't, but the use of "spotify" in its name, and the fact it doesn't disclaim the it's a non-official site probably exposed itself to legal threats.
IANAL but under US law that most certainly wouldn't apply because spotify isn't a "non-public person".
https://en.wikipedia.org/wiki/False_light
My guess is that they used the (still spurious) excuse of trademark infringement, since it uses "spotify" in its name and you could plausibly argue that consumers would be deceived into thinking it's an official spotify site. Most would probably realize it isn't, but the use of "spotify" in its name, and the fact it doesn't disclaim the it's a non-official site probably exposed itself to legal threats.