Because a woman is more than her pregnancy/maternity leave. She may be overwhelmingly the best candidate for the job. The inconvenience of finding maternity cover may be far less inconvenient than hiring a less good person who underperforms and has to be fired, or damages your business
But if a business, especially a small business is looking for an employee, it is because they have a need for them now, not just in 12 months time.
I’ll give you an example. I start a new job at the end of next month. My new employer was looking for someone because they have just won a contract for a project that is lasting 18 months, starting in September. They have submitted my CV to the client as I have been approved and security checked for the project. If I start and in October say I’m going on ML in 4 weeks, I will have spent a month doing all the start up stuff on the project, becoming familiar with it, getting to know the project and the client. They then have 4 weeks to replace me. Most people in my situation are on 3 months notice, so they have to find someone who isn’t (less likely to be experience enough) or have someone fill in until a new person starts, jeopardising their other contracts, then start a new person for however long I’m off, with me returning to finish the project off. The client has no continuity of personnel (something most clients insist on) the employer has been put in a really difficult situation and I’m probably not going to be considered reliable for a long while. It has nothing to do with the impact of paying SMP.
I absolutely think women shouldn’t be discriminated against, but by failing to accept how it can impact on a business we will remain in the situation where businesses find other reasons not to employ women and everyone loses out. There needs to be an open discussion about the difficulties, so these issues can be properly resolved. Only then will we be less likely to be seen as a problem.