Let me give a concrete example. Bed Stuy is a neighborhood in New York City. It is currently facing gentrification, where long term residents (like local shop owners and families) are competing with short term residents (young professionals and tourists). These two forces already competed for rentals, the long term residents controlled the properties.

The short term residents are willing to pay a premium in the form of AirBNB to remain in the neighborhood.[a] This can take the form of a young professional staying in an AirBNB for a month while looking for a rental, or a tourist staying in the neighborhood for a few weeks. This has 3 important effects: 1) AirBNB makes money, 2) an apartment that could have been a rental becomes unavailable to long term residents, and 3) the lister of the AirBNB, who is typically a wealthy long term resident of Bed Stuy, makes a profit.

The result of these 3 factors is a continuous squeeze on poor, long term residents of Bed Stuy. It comes in the form of an increase in price on their most demanding economic cost: housing. (1) and (3) incentive the continuation of this process. (2) contributes to the downfall of the neighborhood in the form of housing instability.

For those who doubt that housing instability contributes to violence, look at the most unstable housing in New York City: the public housing. The wait lists are years long, the applicants are supremely vetted, and felons are generally not allowed. Any yet crime proliferates around the public housing in New York, including in Bed Stuy.

edit:

[a] The flip side of this AirBNB housing premium is experienced by poor, long term residents in the form of rent increases.