As Zamenhof explained both in the opening text (intro) to "Unua Libro" as well as in more detail in the book "Lingvaj Respondoj", there is no distinction.

A quote from Lingvaj Respondoj:
"La formoj “amatas”, “amitas” k. t. p., anstataŭ “estas amata”, “estas amita”, per si mem ne prezentus ian rompon en nia lingvo / "The forms "is-beloved", "was-beloved" etc instead of "is beloved", "was beloved" by themselves would not be a breakage of our language."

A quote from the official 1889 English edition of Unua Libro: 
"I introduced a complete dismemberment of ideas into independent words, so that the whole language consists, not of words in different states of grammatical inflexion, but of unchangeable words...But the structure of such a synthetic language being altogether strange to the chief European nations...will never perceive that the structure of the language differs in any respect from that of his mother-tongue. So, for example, the derivation of frat'in'o, which is in reality a compound of frat “child of the same parents as one’s self”, in “female”, o “an entity”, “that which exists”, i.e., “that which exists as a female child of the same parents as one’s self” = “a sister”..."

A quote from Lingvaj Respondoj: 
"La vorto “bezonesti” estas kunmetita tute regule, kaj vi povas ĝin uzadi. Sed entute ni konsilas pli uzadi ĉiam formojn simplajn anstataŭ kunmetitaj. / The word "is-needs" is a totally regular compound word, and you can use it. But in general we advise to habitually always use words in "simple" forms instead of compounded."

The English Unua Libro is available here: https://www.genekeyes.com/Dr_Esperanto.html

Lingvaj Respondoj is available here: https://tekstaro.com/t?nomo=lingvaj-respondoj

Zamenhof's ideas about linguistic context, taken from those two books and applied to adjective and verb "roots", can be summarized as follows:

- A root (like "hund", "blu") only shows an "idea". It does not show anything about if that idea is a noun, verb, adjective or otherwise.
- "Mi manĝis kuko" is correct even without the accusative, because the kuko cannot logically eat a person. Likewise "Mi blankis la domon" is correct even without "ig" in "blankigis", as it cannot possibly be misunderstood in any way thanks to using the accusative.
- "Mi iriĝas kafejon" is, while not incorrect, not advised, because "I become in a walking state" can be inferred by context, so only "Mi iris - I walk" needs to be used. Likewise "La maro bluas" does not need "blua estas" or "bluiĝas" because no one would misunderstand from context.
- Most people have an easier time reading "blua estas" than "bluestas" or "bluas" but this is just a matter of habit. It does not mean you can't use those forms.
- You are supposed to write Esperanto according to what is most comfortable to both you and the recipient of your Esperanto. Two Greeks can write Esperanto just like Greek, but a Greek writing to a Frenchman should make some adjustments and attempt to write in a way a Frenchman easily understands.

Most modern Esperantists who don't have an Indo-European language as their mother tongue still typically have one as the first second language taught in school. This creates a cognitive bias (linguistic transfer) towards all subsequent foreign language learning - "I learned French in school, so Greenlandic must be like French!". You can read about that in various academic articles. Linguistic transfer is coupled with that Esperanto has spread more rapidly in Indo-European countries. For example, Chinese and Inuktitut can use many words as both adjectives and verbs with no change at all required except for word order: 

1) 愛 - love (noun). 愛犬 beloved dog (adjective), 我愛你 I love you (verb). 
2) qakuqtuq - white. qimmiq qakuqtuq - a white dog (adjective) / the dog is white (verb).

Today in 2024 the majority of people in the world speak English, French or Spanish as a second language if not a first one. A lot of Chinese people are hidden to the outside world due to China's firewall, and there is still no Unua Libro or Esperanto dictionary for any of the Eskimo-Aleut languages.