Actually this is an exception. Its not that "pomidor" is being used as an inanimated object but rather that its been declined as an animated being. Thats why, for example, we say "Kupiłem wazon". We do not say "wazona". Pomidor is declined as kot "lubię kota". The same happends with some foreign words like szampan or mercedes. "Piję szampana" or "lubię mercedesa" even though they are not animated.
All fruit and vegetables are considered animated nouns (except: czosnek and groszek), so we say: jem banana, kup ogórka. The other groups of words that have an ending -a in accusative although they are not animates are (of course we say only about masculine nouns): - meat and fish (jem kurczaka, tuńczyka) - small food (jem pączka, hamburgera, loda, lizaka) - games (gram w tenisa, golfa) - dances (tańczę walca) - currencies (mam jednego dolara, funta) - brands (mam Opla, Mercedesa, Samsunga) - and "new technology (only in spoken language - it is not acceptable in dictionaries but people do say so) - mam facebooka, tweetera, piszę smsa, maila.
jem pomidor , jem ogórek, widzę laptop, podaj mi kartofel, przynieś mi but - this is pure polish language. However, unfortunately, the majority not caring about pureness imposes changes. http://www.ekorekta24.pl/jesc-banan-czy-banana-pomidor-czy-pomidora-ogorek-czy-ogorka/
From previous comments, I understood that when I want to say that I'm eating some food, I treat the food like an animate being. But how do I say "I eat tomato" ("eat" like in "I eat tomato because my doctor told me to") in Polish?
[EDIT: Haha, my mistake. I would say "I eat tomatoes" in English, not "I eat tomato". I got temporarily confused because in Serbian we say "Jedem paradajz" (paradajz from Austrian German "Paradeiser"). "Paradajz" is an exception, for other masculine foods we use plural, for example "Jedem oraje (orahe)" - "I eat walnuts" :)
The question still stands - how do I say that I eat some food in Polish? Do I use plural like in English? Is "Jem pomidory" correct?]
First, I might not be the best advisor about it (since I belong to that part of the Polish speakers that do not animate those nouns, for the most part), but I think it's really not so simple as "masculine food is always masculine animate" – „Jem ryża” instead of „Jem ryż” sounds really wrong, I think it only involves vegetables, but as I said, I'm not sure („Jem selera” instead of „Jem seler” sounds just as wrong to me or in fact, ”jem pomidora”. :P).
As for present simple, it's just translated to Polish „czas teraźniejszy”, there is no real distinction (excluding Verbs of Motion, which also include senses), but if you wanted to say that you eat in general as opposed to eating now, you would indeed go with the plural (where applicable, food generally involves a lot of uncountable nouns, and Polish is no different here).
Also, if you wanted to state that you generally eat some type of food (like stating you aren't a vegetarian by saying "I eat meat"), the best option would be to use habitual version of the verb, so „jadać” – „Jadam pomidory”. It can be said with normal verb („Jem pomidory”) too though, so some Poles never use the habitual verbs – choice of one or the other is a matter of style, mostly.
Unfortunately, there's no clear rule about what food we treat as animate and what not. And about some of them, people could argue (Jem kotleta vs Jem kotlet (a pork-chop, usually) always causes a debate).
Most of those that are treated as animate are indeed fruits and vegetables. But also such things as szampan (champagne), for example. Or hamburger, or kebab.
In Polish we animate COUNTABLE dishes. So you can't say: Jem bigosa, rosoła, gulasza, krupnika, ryża, obiada etc :)
I think that not alive things that we mostly throw in this category are things that we can easly (and often) carry. They are ‘born’ when we say – Podaj mi jednego ‘give me one’.
I saw your post on Facebook, "pomidor" was supposed to be just a distractor (one of the 'wrong' words), and the 'best answer' "pomidora" was also among the tiles. But "pomidor" is also an acceptable option, and I believe people explained to you why :) Still, I'm pretty sure most natives would consider it strange, even if technically it's correct.