I would say that what he meant was that all the birds at the rescue or pet stores etc,especially those in rescues,all have you see this experience with humans and such and even the TAMEST,SWEETEST,LOVELIEST and HAPPIEST BIRD will turn over time,because of hormones and such,or just some new,fresh perspectives to the bird or simply put,NOT ENOUGH ATTENTION! Which is also the main cause cause of birds changing from tame to untame,cuddly to nippy.
Do bear in mind that for WHATEVER BIRD TYPE you get,big or small in the end,you need to know their diet,flight ability,cage space and other pets are a NO NO ( hamsters and guinea pigs still okay,the rest especially cats and dogs are a NO NO NO!!! So by getting a bird,you must ensure that you won't be getting any others pets like those I just mentioned ).
Lorikeets especially are known not only for their vibrant colours,as in Rainbow Lorikeets ( they are lively and are flighty and have a conure-like size so you could check them out too! I am owned by Rainbow Lorikeet Bright now along with my others birds so I could tell you that they are very active and clever but need to keep an eye out for them as they can be too curious ) but also for their nectar,flower,leaves etc diet that they have.They are also on the expensive ( 300-400) range.Sure,they will eat seeds and pellets ( pellets if you must ),as in every bird,but that simply put,isn't the best!
Every bird will be nippy and grumpy when you first bring them back to their new and hopefully,forever home so PATIENCE IS KEY to bond and make your bird TRUST YOU and your family.
Do not,DON'T let your bird in the kitchen if you have telfon pots and pans as the fumes emitted are LETHAL to them.If you are unsure,don't let them in anyway just to be safe.Just some basic tips that I could think of now and I'll get back to you later if you decide on which species of bird you would like to get ( the confirmed,as your thoughts could change ) or if you just want some more tips.Just @ me and I'll respond as fast as I can as my time zone is probably different from yours ( 22 44 at my time now ).
So yeah,hope you'll enjoy your future birb keeping life !