I am British, and while a long term expat now, I am back often and have parents, brother, tons of family in UK and many friends.. including sikhs. This is not some sort of epidemic.
its less of a forced conversions but as you noted …the families can’t handle it, they don’t have control and then in all desi communities, everyone is in everyone’s business, so easier to say that it was a forced conversion than the girl simply did not care for her faith enough or preferred a different faith. Its not just an issue in sikh community but all desi communities (and non desis too). The poor innocent girl was corrupted, controlled, coerced..make her a victim of some controlling jerk and hey, the family is a victim, you can’t say anything about the girl, and hey if things don’t work out…as many times they don’t…
in the end it does not matter why someone converted, the fact remains they converted, even if their routine is the same otherwise..and its just on paper. It is the egos and honors of elders and extended family/clan and communities who just have to be in everyone’s business that make it more than it is.
many desi girls take off with black guys or white boys as well, and guys with non desi girls … larger numbers actually..but that is not made an issue because the historical subcontinental baggage does not apply to egos and honors as much in that case.