Some people argue that Bitcoin is unfair because:
- it dramatically favored early adopters with ~ 10000x returns.
- the coin distribution policy (halving every ~ 4 years) could make it unsustainable to mine in the long-term or drive the prices/fees even higher
- the hash algorithm has been taken over by ASIC industry (still it created a monster network with tremendous hashing power making it near impossible to break)

Altcoins can alleviate this problem by different approach to all above issues.

In my opinion, they are welcome to the crypto - ecosystem. Sure, some have weaker network hash rate which might make them less secure than bitcoin and other disadvantages due to reduced block time (orphan blocks) but still very very welcome.

I reccomend highly coincheckup.com for a lot of information on altcoins.