> almost all European languages belong to one family – Indo-European – and of all of them, English is the only one that doesn’t assign genders that way.
Persian is Indo-European and does not assign genders that way either.
Nor does Armenian or Bengali. But English does. Gender does not affect grammar in English (cf French where conjugation depends on grammar), but it is actually a gendered language with three genders. Almost all nouns are neuter but many animate pronouns can be masculine, feminine, or neuter (people or animals can be referred to as "he", "she", or "it"/"they"). Some inanimate pronouns can also be gendered. For example, ships are often female; you might say something like "she's a beauty" when talking about a boat. There are also a handful of gendered nouns. For example, "actor" and "actress" are masculine and feminine nouns.
Just because a word describe something that is gendered, it doesn't mean that the word is gendered itself. And using gendered pronouns for inanimate things in English is purely result of tradition and has nothing to do with grammar; it is perfectly normal to use "it" for a ship.
> Gender does not affect grammar in English [...], but it is actually a gendered language with three genders.
A definition of a gendered language is that the gender affects grammar, not whether it has (pro)nouns to designate gendered objects.