Sigh.. okay whatever you say, since its your opinion. I'm just stating that this is the common name for English-speaking people as well. So its an English exonym.
"São Tomé and Príncipe" - Google 24,000,000 search results
"São Tomé e Príncipe" - Google 2,190,000 search results
Sites that use "São Tomé and Príncipe" as above in the thread title:-
Official São Tomé and Príncipe Tourism site -
http://www.saotome.st/
IMF (International Monetary Fund) -
http://www.imf.org/external/country/STP/index.htm
World Bank -
http://web.worldbank.org/WBSITE/EXTE...382765,00.html
U.S Department of State -
http://www.state.gov/r/pa/ei/bgn/5434.htm
São Tomé and Príncipe homepage -
http://www.stome.com/
B.B.C -
http://news.bbc.co.uk/1/hi/world/afr...es/1064541.stm
IANA -
http://www.iana.org/root-whois/st.htm
WHO (World Health Organisation) -
http://www.who.int/countries/stp/en/
Is there a need to argue further?

Nope. LOL, a country name that is 'worthless'.
Yes, i can accept it.