"The proposal on banning minaret construction was championed by rightwing and ultra-conservative groups. The government and most political parties as well as churches and the business community came out strongly against it.
To be approved, it needed the backing of a majority of both voters and cantons.
The director of gfs.bern told Swiss French television that the issue by the end of the campaign was not minarets, but the position of Muslims in Switzerland." [...]
"The number of Muslim immigrants has increased to about 350,000 (up to 4.5 per cent of the Swiss population) since the 1990s. Most of them came from the former Yugoslavia and Turkey and are considered moderates.
There are an estimated 160 mosques and prayer rooms in Switzerland, mainly in disused factories and warehouses. Only four of them have a minaret, including the mosques in Geneva and Zurich."
It is worth stating that Switzerland has some very strict rules about architecture. For instance, no building may be so tall as to obscure a view of the Alps. But mostly, this vote seems to have passed based on a fear of Islamicisation in the country and a perception that Muslims do not attempt to integrate into society as much as they should.
SwissInfo | Minaret ban approved, projections show