Meeting is secret is not hiding your conversion. The early church is full of martyrs (and the apostles especially) - not those who run and hide.
If you feel you have to hide your conversion then, rightly so, many believers should question your conversion.
I am a cult deprogrammer and have a transition ministry. I deal with helping people transition out of cults and into Christianity (Mormonism, SDA, JW, Islam, atheism, Scientology, etc) and in all of the cases there is a fear of reprisal - either from the group or its members. Loss of job, loss of friends, loss of family, loss of marriage, loss of life, so this is a topic I deal with on an almost daily basis. And one of the things I help them work though is counting the cost - and following through that what we gain in Christ is more important than what we will lose by publicly confessing him. Another area is teaching them how to witness to their loved ones still in the cult.
There are many ex-muslim converts who are martyred, as you probably know, as well as Christians living among muslims who are likewise martyred. Christians living in many muslim countries like Saudi Arabia typically meet in secret and do not advertise their meetings. Its the only way. And others, like the Assyrians, emigrate to the west when they can. I remember the Afghan who was under a death sentence who they finally got out and relocated to Italy.
The point of the article is that converts could at one time find safety in the west, and that is no longer true, particularly in Italy. You or I could be openly Christian in Italy, because no one would imagine we are converts from Islam. I could be an open Christian in Saudi Arabia, but I can’t meet openly... An arab or iranian Christian pretty much anywhere is in another circumstance. He needs to blend in with non-arabs as quickly as he can to find safety. The US is still pretty safe, I know some Copts and Assyrians, but in the countries accepting mass numbers of “refugees”, they are being openly assaulted.