If the case against Judy Stone and AAS posters and Directors friends is a Strategic Lawsuits Against Public Participation (called SLAPP suits) with the aim of silencing Animal Advocates the idea is generally not to let the case go to court but to drain resources and effort from the financially weaker party and to let the case drag on for years. The aim is not always to win. If you take in around $17 million a year your donors probably won't notice the relatively trivial expense. The weaker party financially is really punished.
Many US states are now clamping down on such lawsuits and throwing them out at the outset. That charities should consider initiating them, which appears to be what the BC SPCA is doing, is beyond belief. You'll have to judge for yourself whether the lawsuit against Animal Advocates is a SLAPP suit.
For details on SLAPP suits see