In y opinion any coin can be called a shitcoin. Even ones with high market caps.
For example: ETC and Dogecoin, to name a pair often called shitcoins. In my humble opinion, that which makes one coin a shitcoin might not make others that share those same traits also shitcoins. In the case of Dogecoin, it's gonna inflate forever and when some doge fans say that there is no inflation because of the lost coins I'd say it doesn't make sense because almost every crypto holder knows how to save crypto safely . It's just a bad store of value in the long term. In my mind, that makes it a shit coin.
However, other people say Ethereum Classic is also a shitcoin because, well, insert XYZ explanation here.
In the case of ETC, I believe it's not yet found all its use cases, but there are projects using it are working with it, and it has a pretty decent market cap and trade value, compared to a vast majority of other cryptocurrencies.
However, if you bought ETC at $30, before it mooned to over $100 during the early bull run this year, you probably won't be calling ETC a shit coin, because you made some serious gains on that buy.
Even still, others call Bitcoin and Ethereum themselves as shitcoins, choosing to put all their love in TRX, or Litecoin, or even SHIBA. :
That being said, most coins TRULY that earn the moniker "shitcoin" fit one or more of these 3 criteria
-It's got a low value, probably under a penny but almost always under $10
-it's got a poor long-term value equation, so people didn't want to hodl it and sold it at the ath
-or, finally it's functionally worthless because it's project has unfulfilled ambitions/promises and/or has been abandoned by its creators.
So, based on that definition, people who call ETC, BTC, and ETH shitcoins just because "i don't like the project" are just being pejorative. The truth is, all of those projects fail to meet all 3 of my shitcoin criteria.