They can be. And ships aren't always going to be facing ships in similar roles at the same teirs of ship. If you are new to the game, you can purchase a ship with better stats than a sidewinder and not only invalidate the gameplay, but also gain an unfair advantage over players who don't have the money to buy better ships right out of the gate.
You do realise that you can get an Annie within a few days (arguably still the best allrounder in the game), fed rank for a Vette and Imp rank for a cutter within two weeks?
That new ARX ship really makes no difference.
Your talking here about the kickstart ships with some engineering? This has been discussed before, Elite is an old game, just like any other successful game that has been running a while (EQ,WOW,GW2,ESO etc) they offer a leg up to new players so that they can instantly join the action, not better ships, just ships that can at least compete in a world with years of new modules and engineering.
Try competing with my 20+ year old Necro in EQ, you wont and would get bored fast if you didn't at least have a leg up with a purchased character.
O7