I can't speak on the mentioned revolutionaries in particular but I can provide some insight more generally to political exiles in the 19th century. The idea of Swiss neutrality was well developed by this period and the nations geographic position, especially bordering the political and particularly nationalist hotbeds of Germany and Italy, made the nation an ideal place for fleeing revolutionaries to travel to after their home countries became too dangerous. The mountainous passes of south Switzerland were excellent launching points for Italian revolutionaries, used by a young Giuseppe Garibaldi and his fellows in the Young Italy movement.

It was difficult to apply pressure on Switzerland due to its almost inert political position, especially as it was a position established with the support of the great powers of Europe in particular after the post-Napoleonic congress of 1815. It was not impossible, however, and some particularly troublesome dissidents were driven out of the country. From my example of the Young Italy movement above, Giuseppe Mazzini was arrested in Solothurn, Switzerland and exiled from the country in 1834.

Finally, dissidents may want to flee their country when threatened with arrest as especially in the nineteenth century, dissidents could not be sure that their life and safety were guaranteed in custody. Executions of prominent revolutionaries were common and for most the opportunity of exile, with the possibility of returning later when the situation in the country was more favourable, was a preferable choice.

Anarchist and Communist movements in Switzerland were certainly suppressed as in many other countries across Europe but there were greater allowances for the activities and distribution of revolutionary propaganda. Bakunin in 1867 noted there were tangible differences of Switzerland from other nation states, as this quote from his criticism of Rousseau in "Rousseau's Theory of the State,"

What do we really see in all states past and present, even those endowed with the most democratic institutions, such as the United States of North America and Switzerland? Actual self-government of the masses, despite the pretense that the people hold all the power, remains a fiction most of the time. It is always, in fact, minorities that do the governing...

But the police and State certainly were not hands off political agitators. For instance in 1878 the Swiss authorities shut down the press L'Avant Garde following its support of the assassination of King Alfonso in Spain. One of its editors Paul Brousse had been arrested multiple times and ultimately deported in the same year. Though prior to this string of articles L'Avant Garde had been considered "legal." Peter Kropotkin, then another editor of the paper and later noted Anarchist-Communist and publisher of the Swiss paper Le Revolte, noted in his autobiography "Memoirs of a Revolutionist," of the Swiss' transition from a hands-off approach to one of more direct interaction with the socialists and anarchists.

[A]ll the European governments fell upon Switzerland, reproaching her with harboring revolutionists, who organized such plots. Paul Brousse, the editor of our Jura newspaper, the “Avant-Garde,” was arrested and prosecuted. The Swiss judges, seeing there was not the slightest foundation for connecting Brousse or the Jura Federation [the anarchist international organization] with the recent attacks, condemned Brousse to only a couple of months’ imprisonment, for his articles; but the paper was suppressed, and all the printing-offices of Switzerland were asked by the federal government not to publish this or any similar paper. The Jura Federation thus remained without an organ.

Besides, the politicians of Switzerland, who looked with an unfavorable eye on the anarchist agitation in their country, acted privately in such a way as to compel the leading Swiss members of the Jura Federation either to retire from public life or to starve...

Peter Kropotkin himself was expelled from Switzerland following the death of Alexander II in 1881. Kropotkin's statements, that "all the european governments fell upon Switzerland..." is not without its supportive theories, though the danger of separating theory and conspiracy theory would be too great to get into. Suffice to say that the greatest push against anarchists in the country would not occur until the later 1880's and early 1890s following the failed bombing by Russian anarchists in 1889. In 1894 both Italy and Switzerland would release "anti-anarchist" legislation following the Lunigiana revolt. Richard Bach Jensen, in his book "The Battle Against Anarchist Terrorism" claims that,

the Swiss law of April 12, 1894 appears to have been the first anti-anarchist law explicitly directed against "terrorism," since it stated that "whoever, with the intention of spreading terror in the population or disturbing public security, incites to commit crimes against persons or property, or gives instruction for their [explosives] preparation" would be punished.