It's really not that hard to understand - I can only assume you are trying to willfully misunderstand it. Let's take it out of the current context to see if you can wrap your head around it. If I were to say "I support the civil rights movement in the USA of the 1960s, but disagree with the actions [and many views] of the Black Panthers", would that be fence sitting, or just a broadly sensible thing to say? I ask again - do you endorse everything Johnson says because he led the Leave vote and the Party you voted for in 2019? Or are you capable of independent thought, or 'fence sitting' as you put it?
As for the defund the police statement - I've still not seen that on any of their official sites, but I have no issue with the tweet in that article. "When we say 'Defund the police' we mean 'Invest in programmes that actually keep us safe like youth services, mental health and social care, education, jobs and housing. Key services to support the most vulnerable before they come into contact with the criminal justice system'. That's precisely the sort of holistic multi-disciplinary approach that worked with white on white violence in Glasgow.