Technically, abortion applies to embryos and fetuses. An egg is referred to as an embryo once it's fertilized, regardless of implantation. Therefore, any removal of the egg once it's fertilized (embryo) is, definitionally, an abortion. (I know individuals have their own interpretations, of course.)
The emergency contraceptives can work in the following ways:
1) inhibit or delay ovulation (no fertilization, no abortion)
2) inhibit tubal transport of the egg or sperm (no fertilization, no abortion)
3) interfere with fertilization (no fertilization, no abortion)
4) alter the endometrium (the lining of the uterus) which inhibits implantation of a fertilized egg (fertilization, chemical abortion)
So, in one case, the ECP is an abortion. In 3 cases, it is not. So, everyone's right in a way.