You are very wrong but I don't blame you because the whole Somali society thinks they know things when they don't know a thing about it. It is in their nature to claim to be experts of all and everything.
The Somali understanding or what they think they understand about Oromo is completely wrong. Oromo are not like Somalis where we are all the same and we have slight dialogue and accent difference and dozens of major clans and hundreds of sub-clans. Oromo is completely different. If you can understand Oromo, you have just graduated the highest university in Ethiopia. Congratulations!
Somalis used to have contacts with people such as Jarso, Gurgura and few other long lost Dir clans and they think thats Oromo. These people are long lost Dir clans and to this day some claim to be Somali while others claim to the modern day invented "Oromo" ancestry. They claim they are part of Afraan Qallo. Having lived in Diredawa, I know how confusing this is. I had many friends who were Jarso and some claimed Somali and spoke Somali fully and others claimed Oromo and spoke their own Oromo language. Oromo from Shewa and even Bale would have hard time understanding them.
Then we have the Arsi Oromo and the Qallu and again Somalis think all Oromo must be like those two but little do they know how different Oromos are from every district and village.
In reality there is no such thing as proper definition/identification of "Amhara" or "Oromo".
The Oromo and the Amhara are pretty much one and the same thing in many ways. It is like saying George Bush is Saxon and others arguing no he is Angles.
Many of Ethiopia's great leaders are today identified as "Oromo" including Emperor Haile Selassie, Emperor Iyasu V, Mikael Ali (King of Wollo), Makonnen Wolde Mikael, Balcha Aba Nefso and many many others including Emperor Menelik.
The "Oromo", "Amhara" and Gurage are three assimilated groups and it was only recently in the 19th century that groups from the east began labeling itself as Oromo. Before that many of these groups were simply referred to as Galla.
In short, just because you saw some light skin girls speaking Amhara doesn't mean they are Amhara...God knows what their true background is. They could be Wollo Oromo.
The modern Ethiopia was ruled by Shewa groups and these groups were often identified as Oromo speaking Amhara language with Amhara culture and Amhara religion and thus were identified as Amhara. They include mainly the Raya Oromo and the Yejju Oromo. One man summed up:
In terms of descent, the group that became politically dominant in Shewa – and Subsequently in Ethiopia – was a mixture of Amhara and Oromo; in terms of language, religion and cultural practices, it was Amhara.
There is no such thing as a true Oromo. All the leaders of Ethiopia often history denoted as Amhara were Oromo Shewa (Wollo Oromo). It was only when they took the rule in the House of Solomons that the Tigray/Tambien (historical rulers of Habesha/Abyssinia including Eritrea with capital Aksum) lost power and influence because now this new Shewa group was making huge progress and all of a sudden the little known "Amhara" language had millions of speakers.
The Tigreans are different and like us Somalis, they did not assimilate into those groups.
Amhara is Oromo and Oromo is Amhara sxb. Its like saying America ayan uu kala saraya Angles iyo Saxon. Good luck.
Finally genetically we are close to the Afraan Qallo because we have Dir clans carrying our genes that assimilated into them such as the Jarso and Gurgura but can Somalis share genetics with Wollo Oromo from Shewa or even the Worji Oromo? The answer is no way.
