Do you actually drink not-bottom-of-the-barrel sencha? If not, your experience is not applicable, respectfully. With even middle-of-the-road sencha the difference is far from subtle.
i don't know if it's related but i've also noticed i'm much more tolerant of ginger than most people and i can't taste cardamom (seed of the ginger plant, interestingly) at all.
hey, people are different.
Shincha would just refer to freshly picked sencha, for one.
"Green tea" would be 緑茶 (ryokucha). Hojicha is not ryokucha nor green.
Matcha and Sencha are the same plant, only differing in growing conditions and processing.
Several of these words are talking about different aspects of tea. A shincha (fresh) gyokuro (variety+growing method) genmaicha (rice-puffs added; technically doesn't have to involve green tea) is still a sencha (plant+processing) and therefore a ryokucha (plant+color). Listing fukamushi as a "sencha type", but shincha as distinct from sencha, while calling houjicha "green tea" is incorrect and coupled with some quite obscure ones, you just seem to be dropping words without substance. It's like calling rose a "red wine".
(obv all of these words are the same plant species)
Just like with wine there can be no-end to nitpicking if you're looking for it but you don't need to know anything at all to appreciate it and find what you personally enjoy regardless of what snobs would tell you. You started it, though ;)