Luckily the figures don't unlock exclusive content - everything in Smash is available in-game, the figures are just a CPU player you can train/fight. If this had been a situation where you can't play as Marth without the Marth figurine then there'd really be something to be upset about.
I agree but since trained Amiibo are better than level 9 CPU, it is still extra "content". It's the equivalent to a new difficulty level in any other game for me.