How could Yosef kiss his father? It is harmful to do so, due to the power of Tum'as Mes!
Or ha'Chayim: Tum'as Mes did not apply to Ya'akov, seeing as he did not die.
Refer to 49:33:2:1. See Or ha'Chayim. (How will he answer for R. Yehoshua? After R. Eliezer died, he kissed him - Yerushalmi Shabbos 20b. PF)