For x86, because we don't have any "special" symbols, the output is the same for strip vs nostrip. ".word 0x9090" which is data is interpreted as code because of the linear disassambly behavior. The special symbols are documented here: https://sourceware.org/binutils/docs-2.23/as/ARM-Mapping-Symbols.html
For ARM objdump (and the tools alike), because symbols are used to determine if we have code ore data the linear disass knows where is data and where is code.