Considering how many desokupa services exist I'd say it's a real problem.
That's why people sing contracts of X years, and asks for employment contracts and a minimum quantity of money in the bank. In this situations you can still get it wrong, but that's investing, it's always risky.
None of what you said sounds like a problem. What is the problem? It sounds like a policy to ensure dwellings, which are obviously a scarce resource in those areas have actual people living in them. That is kind of their point. Of course it would be beneficial to have a better legal framework to ensure housing security and building maintenance.
I'm assuming from reading your other comments you're not going to be sympathetic to this argument so let me give you two anecdotal incidents.
The first is about a woman who is 70 years old. She lives off a state pension which is supplemented by a small rental income from a three bedroom apartment she owns. The apartment is quite old, and needs refurbishment, so she can only generally rent it to students or non-professionals who pay a modest rent. After maintenance costs, property tax, and building management fees she doesn't get much but enough so she doesn't have to rely on her children.
One day, one of the tenants stopped paying rent. Rather than asking him to leave immediately she gave him some extra time to get the rent. Rather than do this, he decided he would do an occupation. So first he terrorized the other tenants so they left and then proceeded to occupy the entire apartment, including turning one bedroom into a gym. Police were called quite a few times but they said they couldn't do anything until they received a court order. So for a year and a half, this guy lived there rent free with water and electricity being paid for as well (you can cut off internet as it's not deemed essential).
When the court order finally came through the police didn't even bother showing up and it was the locksmith who chased the guy out. He hasn't faced any consequences and could continue to do this again and again. As for the owner, she had to take out loans (some with 20% interest) cover the costs this guy incurred. She, who is Spanish, will never rent out to Spanish people again.
The second is about a taxi driver in his late 40s. After a long period of saving he managed to save enough for a deposit to get a mortgage on a costal apartment that his family would use in the summers and rent the rest of the time. While he could have just listed it on Airbnb, he decided to rent it out to a woman with children on a long-term basis (non-summer months).
So she moves in and when he comes a few days later to collect the first month's rent he's informed that she won't be paying rent and because of the children it's going to be impossible to kick her out. He tries to negotiate with her over a few months, including talking to the town hall to get some some rent stipend, all to no avail. Eventually, he had to use desokupa services to get her out but not before this woman had caused significant property damage.
He also went into debt and his marriage almost failed because of the stress and financial strain. Once he finishes repairing all the damage (which he has to do himself as he can't afford to pay someone else) he will rent it out again but only through Airbnb to foreigners.
So this policy has ensured that honest people, renters and landlords, get punished by dishonest people who won't see any consequences either.
I also think the right to have a home should prevail over the right to make money renting houses.
I also think goving credits to everybody in 2000 fucked up Spain. Everybody +40 in my family owns 2 or 3 houses. Nobody less than 40 owns one.
After the eviction takes place, how badly does an eviction on record hurt the renter's ability to rent in the future? Just trying to understand the asymmetry of costs for the landlord and renter in this situation where the renter "decides" to stop paying rent
The effect of this is more reluctance to rent out for fear this will happen. Or only rent to rich foreigners who won't pull this scam. Lest the landlord find themselves in debt.
Also, the okupa is very much deciding to do this knowing they can get away with it.
How many does exists? I've only heard of one (literally called "Desokupa"), but you're saying there are many companies offering this, not just local chapters of the major one?
Tried searching but could only find that one, and I couldn't find any sources on the number of companies existing offering this service either.
Despite all the publicity, I've never heard of anyone using the company you referenced. At least not in Andalucía.