Well, it's an opinion that can be easily swayed if you simply research the subject matter.
The concept of secular law, at least in America, is based around building a fair society.
There is no such thing as a fair society, I don't personally think it is possible.
However, working towards that shouldn't be something that is deemed "bad".
Secular law is meant to ensure all religions are treated fairly and nothing that goes against their religion is forced upon them.
It also is there to ensure non-religious people aren't forced to follow religious ideology.
Gay marriage was legalized. Why?
Because from a secular, and constitutional, perspective, being gay and getting married isn't harmful to society in any way.
Does this mean that, say, the Christians have to marry gays within their churches, or at all? No, they do not.
This is one of a very long list of examples I can give.
Can you please provide the basis of your opinion?
I wont simply say that you are wrong because reasons x, y, and z.
I would just like to know if you were fed a propagated misconception about secular law.