Motorcyclists and moped riders alike face a lack of parking space in cities. In Ljubljana, they have even started fining motorcyclists for parking incorrectly, and will probably do so elsewhere.
The ZVCP regulates parking for vehicles, but does not distinguish between two-track vehicles and other vehicles. Moreover, under the ZVCP, a cyclist could also be penalised for incorrect parking.  But what is the essence of improper parking? To stop people parking everywhere AND to stop traffic or other activity. A motorcyclist does not do that (with some exceptions).
Ljubljana has parking for motorbikes and mopeds in three places. But this is far too little. Especially because people don't ride motorbikes just for fun, but there are several reasons. You're faster, more agile, you don't create crowds, you don't take up so few parking spaces, you pollute less, and on and on. Statistically, there is only one, or at most two, people in a passenger car, and if you compare a car or a motorbike, then a motorbike is much more ecological than any other motor vehicle.
So here is what needs to be done. Either increase the number of parking spaces for motorbikes or stop pointlessly penalising people for parking incorrectly. A motorcyclist cannot take a parking space from a vehicle because the crowding will be even greater. Wherever there are car parks, there should also be motorcycle parks. In winter, cars could park there, but not otherwise. If they cannot provide this, then they cannot fine a motorist who parks his motorbike in a place that does not bother anyone. Still less that such a motorbike is "groped". It is not the point of a motorbike that you drive into a car park and then walk for half an hour to get to your destination. But I think that every motorcyclist is willing to park in a well maintained place if there are enough of them and they are almost everywhere (those few scofflaws who have to drive to the pub when they come for a coffee should just be fined).
Motorcyclists do not need much, but the government must realise that there are a lot of motorbikes, mopeds and scooters in the cities (if I may specifically mention this category of two-wheelers). In foreign countries, motorcyclists are treated differently, and they also have more parking spaces (just look at Trieste for an example). The fact is that if you ask someone to obey some rules, you have to make it possible for them to actually obey those rules. If you cannot ensure that, then you cannot punish him.
ADDENDUM for reflection: At the end of 2008, the number of motorcycles (including motorised bicycles) in Slovenia was 7.85% of the number of passenger vehicles (http://www.stat.si/novica_prikazi.aspx?id=2367)! What is the ratio in terms of parking spaces?! In Ljubljana, there are supposed to be a total of 4,900 outdoor parking spaces in the city centre (http://www.ljubljana.si/si/zivljenje-v-ljubljani/promet-infrastruktura/parkiranje-v-ljubljani/). How many of these parking spaces are for motorcyclists? Maybe 385, depending on the percentage of motorcycles? Not nearly that many! But this figure is only for the city centre ...